Electronic and transport properties of porous graphenes: Two-dimensional benzo- and aza-fused π-conjugated-microporous-polymer sheets and boron-nitrogen co-doped derivatives

Inspired by recent successful synthesis of porous frameworks based on aza-fused conjugated-microporous-polymers (Angew. Chem. Int. Ed., 2011, 50, 8753-8757), we investigate electronic and electron transport properties of two-dimensional (2D) benzo-conjugated-microporous-polymer (benzo-CMP) and aza-CMP sheets and their boron-nitrogen (BN) co-doped derivatives using density-functional theory calculations and the non-equilibrium Green's function (NEGF) method. Both benzo-CMP and aza-CMP possess pore diameters about 12 Å and both are semiconductors with a direct bandgap of 0.92 and 1.07 eV, respectively. The BN co-doped derivatives possess smaller bandgaps (0.47 to 0.6 eV). Computed current-voltage (I-V_b) curves are consistent with the semiconducting properties for all 2D systems. The tunable electronic and electron transport properties via BN co-doping offered by benzo-CMP and aza-CMP may be exploited for applications in low-dimensional electronics.