Wang Xian, Ma Xingtao, Zhang Li, Jiang Gang, Yang Mingli
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, 610065, China.
J Mol Model. 2019 Aug 23;25(9):266. doi: 10.1007/s00894-019-4127-z.
Chemical synthesis for graphenes with uniform pore structures opens a new way for the precise modulation toward the performances of graphene-based materials. A family of porous graphenes with continuous and ordered pore distributions was designed by tracking the synthetic paths and studied by using density functional theory calculations. Three compounds with different pore sizes and orientations have remarkably different energy band structures. Introduction of pores opens the band gap of graphene. While the valence band maximum (VBM) is subject to small changes, the conduction band minimum (CBM) shifts with pore size and orientation. Furthermore, distinct in-plane anisotropy was noted in electron delocalization for the VBM and CBM bands. Enlargement of pore size alters the electron delocalization between the longitudinal and transverse directions. Confined by the ribbons and bridges that are separated by pores, electric dipoles cost more energy to respond to the applied fields, and electron excitations become more difficult in less conjugated systems. Our calculations reveal that for the graphenes with uniform pore structures, their band structures and optoelectronic properties are expected to be modulated by careful control over pore size and orientation through chemical synthesis.
具有均匀孔结构的石墨烯的化学合成开辟了一条精确调控基于石墨烯材料性能的新途径。通过追踪合成路径设计了一系列具有连续且有序孔分布的多孔石墨烯，并使用密度泛函理论计算对其进行了研究。三种具有不同孔径和取向的化合物具有显著不同的能带结构。引入孔会打开石墨烯的带隙。虽然价带最大值（VBM）变化较小，但导带最小值（CBM）会随着孔径和取向而移动。此外，在VBM和CBM能带的电子离域中观察到明显的面内各向异性。孔径的增大改变了纵向和横向之间的电子离域。由于被孔分隔的条带和桥所限制，电偶极子在响应外加场时需要消耗更多能量，并且在共轭程度较低的体系中电子激发变得更加困难。我们的计算表明，对于具有均匀孔结构的石墨烯，通过化学合成仔细控制孔径和取向有望调控其能带结构和光电性能。
