Leonardo D. Machado Cristiano F. Woellner, Pedro A. S. Autreto<\/p>
The Influence of Morphology on the Charge Transport in Two-Phase Disordered Organic Systems<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc., <\/span>vol. 1737, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Woellner2015,\r\ntitle = {The Influence of Morphology on the Charge Transport in Two-Phase Disordered Organic Systems},\r\nauthor = {Cristiano F. Woellner, Leonardo D. Machado, Pedro A. S. Autreto, Jose A. Freire, Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9707375&fulltextType=RA&fileId=S1946427415005023},\r\ndoi = {10.1557\/opl.2015.502},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc.},\r\nvolume = {1737},\r\nabstract = {In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.502<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Mater. Res. Soc. Symp. Proc., <\/span>vol. 1737, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Woellner2015,\r\ntitle = {The Influence of Morphology on the Charge Transport in Two-Phase Disordered Organic Systems},\r\nauthor = {Cristiano F. Woellner, Leonardo D. Machado, Pedro A. S. Autreto, Jose A. Freire, Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9707375&fulltextType=RA&fileId=S1946427415005023},\r\ndoi = {10.1557\/opl.2015.502},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc.},\r\nvolume = {1737},\r\nabstract = {In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.502<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Woellner2015,\r\ntitle = {The Influence of Morphology on the Charge Transport in Two-Phase Disordered Organic Systems},\r\nauthor = {Cristiano F. Woellner, Leonardo D. Machado, Pedro A. S. Autreto, Jose A. Freire, Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9707375&fulltextType=RA&fileId=S1946427415005023},\r\ndoi = {10.1557\/opl.2015.502},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc.},\r\nvolume = {1737},\r\nabstract = {In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.502<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{Woellner2015,\r\ntitle = {The Influence of Morphology on the Charge Transport in Two-Phase Disordered Organic Systems},\r\nauthor = {Cristiano F. Woellner, Leonardo D. Machado, Pedro A. S. Autreto, Jose A. Freire, Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9707375&fulltextType=RA&fileId=S1946427415005023},\r\ndoi = {10.1557\/opl.2015.502},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc.},\r\nvolume = {1737},\r\nabstract = {In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.502<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div>In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor\/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.502<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.502<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/div><\/div>2.<\/div> Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Autreto, Pedro A. S.; Galvao, Douglas S.<\/p>
Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation<\/a> Journal Article<\/span> <\/p>In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Mater. Res. Soc. Symp. Proc. , <\/span>vol. 1726 , <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{Autreto2015,\r\ntitle = {Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation},\r\nauthor = {Pedro A. S. Autreto and Douglas S. Galvao},\r\nurl = {http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=9702693&fulltextType=RA&fileId=S1946427415004649},\r\ndoi = {10.1557\/opl.2015.464},\r\nyear = {2015},\r\ndate = {2015-05-22},\r\njournal = {Mater. Res. Soc. Symp. Proc. },\r\nvolume = {1726 },\r\nabstract = {Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div>Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of \u03b1, \u03b2, and \u03b3 graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the \u03b1, \u03b2, \u03b3-graphyne structure ordering.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/i>http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=970[...]<\/a><\/li><\/i>doi:10.1557\/opl.2015.464<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/div><\/div>3.<\/div> Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Lagos, MJ; Autreto, PAS; Bettini, J; Sato, F; Dantas, SO; Galvao, DS; Ugarte, D<\/p>
Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Journal of Applied Physics, <\/span>vol. 117, <\/span>no. 9, <\/span>pp. 094301, <\/span>2015<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{Lagos2015,\r\ntitle = {Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains},\r\nauthor = {Lagos, MJ and Autreto, PAS and Bettini, J and Sato, F and Dantas, SO and Galvao, DS and Ugarte, D},\r\nurl = {http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625},\r\nyear = {2015},\r\ndate = {2015-01-01},\r\njournal = {Journal of Applied Physics},\r\nvolume = {117},\r\nnumber = {9},\r\npages = {094301},\r\npublisher = {AIP Publishing},\r\nabstract = {We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div>We report here an atomistic study of the mechanical deformation of Au x Cu (1\u2212 x ) atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfaces that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/i>http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/9\/10.1063\/1.4913625<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/div><\/div>4.<\/div> Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Ozden, Sehmus; Autreto, Pedro AS; Tiwary, Chandra Sekhar; Khatiwada, Suman; Machado, Leonardo; Galvao, Douglas S; Vajtai, Robert; Barrera, Enrique V; M. Ajayan, Pulickel<\/p>
Unzipping Carbon Nanotubes at High Impact<\/a> Journal Article<\/span> <\/p>In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Nano letters, <\/span>vol. 14, <\/span>no. 7, <\/span>pp. 4131\u20134137, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{ozden2014unzipping,\r\ntitle = {Unzipping Carbon Nanotubes at High Impact},\r\nauthor = {Ozden, Sehmus and Autreto, Pedro AS and Tiwary, Chandra Sekhar and Khatiwada, Suman and Machado, Leonardo and Galvao, Douglas S and Vajtai, Robert and Barrera, Enrique V and M. Ajayan, Pulickel},\r\nurl = {http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nano letters},\r\nvolume = {14},\r\nnumber = {7},\r\npages = {4131--4137},\r\npublisher = {American Chemical Society},\r\nabstract = {The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div>The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/i>http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/nl501753n<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/div><\/div>5.<\/div> Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Autreto, PAS; de Sousa, JM; Galvao, DS<\/p>
Site-dependent hydrogenation on graphdiyne<\/a> Journal Article<\/span> <\/p>In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Carbon, <\/span>vol. 77, <\/span>pp. 829\u2013834, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{Autreto2014,\r\ntitle = {Site-dependent hydrogenation on graphdiyne},\r\nauthor = {Autreto, PAS and de Sousa, JM and Galvao, DS},\r\nurl = {http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Carbon},\r\nvolume = {77},\r\npages = {829--834},\r\npublisher = {Pergamon},\r\nabstract = {Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div>Graphene is one of the most important materials in science today due to its unique and remarkable electronic, thermal and mechanical properties. However in its pristine state, graphene is a gapless semiconductor, what limits its use in transistor electronics. In part due to the revolution created by graphene in materials science, there is a renewed interest in other possible graphene-like two-dimensional structures. Examples of these structures are graphynes and graphdiynes, which are two-dimensional structures, composed of carbon atoms in sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two acetylenic groups) were recently synthesized and some of them are intrinsically nonzero gap systems. These systems can be easily hydrogenated and the relative level of hydrogenation can be used to tune the band gap values. We have investigated, using fully reactive molecular dynamics (ReaxFF), the structural and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes. Our results showed that the hydrogen bindings have different atom incorporation rates and that the hydrogenation patterns change in time in a very complex way. The formation of correlated domains reported to hydrogenated graphene is no longer observed in graphdiyne cases.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/i>http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0008622314005429<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/div><\/div>6.<\/div> Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Vinod, Soumya; Tiwary, Chandra Sekhar; da Silva Autreto, Pedro Alves; Taha-Tijerina, Jaime; Ozden, Sehmus; Chipara, Alin Cristian; Vajtai, Robert; Galvao, Douglas S; Narayanan, Tharangattu N; Ajayan, Pulickel M<\/p>
Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers<\/a> Journal Article<\/span> <\/p>In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Nature communications, <\/span>vol. 5, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{Vinod2014,\r\ntitle = {Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers},\r\nauthor = {Vinod, Soumya and Tiwary, Chandra Sekhar and da Silva Autreto, Pedro Alves and Taha-Tijerina, Jaime and Ozden, Sehmus and Chipara, Alin Cristian and Vajtai, Robert and Galvao, Douglas S and Narayanan, Tharangattu N and Ajayan, Pulickel M},\r\nurl = {http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html},\r\nyear = {2014},\r\ndate = {2014-01-01},\r\njournal = {Nature communications},\r\nvolume = {5},\r\npublisher = {Nature Publishing Group},\r\nabstract = {Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.},\r\nkeywords = {},\r\npubstate = {published},\r\ntppubtype = {article}\r\n}\r\n<\/pre><\/div>Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div>Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal \u200bboron nitride (h-BN) platelets. The ultra-low density (1\/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.<\/div>Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/i>http:\/\/www.nature.com\/ncomms\/2014\/140729\/ncomms5541\/full\/ncomms5541.html<\/a><\/li><\/ul><\/div>Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Close<\/a><\/p><\/div><\/div><\/div>7.<\/div> Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Gao, Guanhui; Mathkar, Akshay; Martins, Eric Perim; Galv ao, Douglas S; Gao, Duyang; da Silva Autreto, Pedro Alves; Sun, Chengjun; Cai, Lintao; Ajayan, Pulickel M<\/p>
Designing nanoscaled hybrids from atomic layered boron nitride with silver nanoparticle deposition<\/a> Journal Article<\/span> <\/p>In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
In: <\/span>Journal of Materials Chemistry A, <\/span>vol. 2, <\/span>no. 9, <\/span>pp. 3148\u20133154, <\/span>2014<\/span>.<\/p>Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
Abstract<\/a><\/span> | Links<\/a><\/span> | BibTeX<\/a><\/span><\/p>@article{gao2014designing,
@article{gao2014designing,