Polaron transport in porous graphene nanoribbons

Abstract

Porous graphene (PG) forms a class of graphene-related materials with nanoporous architectures. Their unique atomic arrangements present interconnected networks with high surface area and high pore volume. Some remarkable PG properties, such as high mechanical strength and good thermal stability, have been widely studied. However, their electrical conductivity, and most importantly, their charge transport mechanism are still not fully understood. Herein, we employed a numerical approach based on a 2D tight-binding model Hamiltonian to first reveal the nature of the charge transport mechanism in PG nanoribbons. Results showed that the charge transport in these materials is mediated by polarons. These carrier species are dynamically stable and present very shallow lattice distortions. The porosity allows for polaron-like charge carriers, and it can preserve the PG semiconducting character even in broader nanoribbons. The polarons move in PG within the optical regime with terminal velocities varying from 0.50 up to 1.15 Å/fs. These velocities are lower than those for polarons in conventional graphene nanoribbons (2.2–5.1 Å/fs).