Abstract
The major hindrances of implementing graphene in two-dimensional (2D) electronics are both mechanical (the tendency to crumble and form ripples) and electrical (the lack of a band gap). Moreover, the inevitable structural defects in graphene have a profound influence on its physical and chemical properties. Here, we propose a family of 2D egg-tray graphenes constructed by arranging pentagon and heptagon defects in the graphene lattice based on a careful analysis of the topological distribution of minima, maxima, and saddle points. First-principles calculations show that the egg-tray graphenes are dynamically stable, and their energies, which depend on the concentration of pentagons and heptagons, are the lowest among carbon allotropes. These 2D carbon allotropes exhibit a large variation in their electronic properties, ranging from semimetallic to semiconducting, including some allotropes that have Dirac cones in their band structures. Furthermore, some egg-tray graphenes are predicted to have negative Poisson’s ratios. The adsorption of Li atoms on the egg-tray graphenes is considerably stronger than the adsorption on perfect graphene, therefore they may absorb Li more effectively than graphene, which is important for improving the performance of rechargeable Li batteries.
Highlights
Graphene has become a superstar in both academia and industry, ever since its discovery in 2004.1–3 Perfect graphene is a oneatom-thick layer of sp[2] carbon atoms arranged in a honeycomb lattice, and it has shown many outstanding properties such as the room-temperature Hall effect,[4] ambipolar field effect,[1] exceptional carrier mobility,[5,6,7] and high thermal conductivity,[8] etc
Some studies have shown that structural defects can locally increase the reactivity of graphene and provide adsorption sites for atoms or molecules, which is very important for the catalytic applications of graphene
We propose a strategy to study the arrangement of structural defects in the graphene lattice
Summary
Graphene has become a superstar in both academia and industry, ever since its discovery in 2004.1–3 Perfect graphene is a oneatom-thick layer of sp[2] carbon atoms arranged in a honeycomb lattice, and it has shown many outstanding properties such as the room-temperature Hall effect,[4] ambipolar field effect,[1] exceptional carrier mobility,[5,6,7] and high thermal conductivity,[8] etc. The insertion of one pentagon into the graphene sheet will produce a surface with positive Gaussian curvature, namely a carbon nanocone, which has been predicted to be a promising candidate as a phononic device and electronic sensor.[17,18,19] On the other hand, the presence of one heptagon or octagon in the graphene sheet will lead to a negatively curved surface, which is a structural feature that is desirable for applications in alkali-ion batteries.[20] considering the important structure–property relationships in carbon allotropes, it is necessary to systematically study systems with different arrangements of these nonhexagonal rings in the graphene lattice. By arranging nonhexagonal rings in the graphene lattice according to topological diagrams, we obtain a series of two-dimensional (2D) carbon allotropes possessing hillocks and trenches Their thermodynamic stability as well as electronic and mechanical properties is thoroughly investigated using first-principles calculations.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
