Dielectric and optical properties of porous graphenes with uniform pore structures.

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.