npj: 蛋盒石墨烯—奔向电子材料的基础性突破

来源：知社学术圈

石墨烯是目前学术界和工业界最有前途的材料之一。尽管石墨烯表现出许多优异的性能，但有两个关键问题限制了它的应用。作为单原子层材料，石墨烯很容易折叠或形成褶皱。另外它缺乏带隙，很难成为大规模集成电路的基底材料。那么能否通过改变或调制石墨烯的几何形态来改变它的性能，从而达到同时克服上述两个困难的目的呢？

该文近期发表于npj Computational Materials 5: 71 (2019)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。

Building egg-tray shaped graphenes that have superior mechanical strength and band gap 

Wei Liu, Lei Zhao, Eva Zurek, Jing Xia, Yong-hao Zheng, Hai-qing Lin, Jing-yao Liu & Mao-sheng Miao

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.