Elastic and electronic properties of oxygen plasma-treated graphene sheets from first principles

Abstract

Mechanical and electronic properties of oxygen plasma-treated graphene sheets are investigated using density functional theory (DFT). Oxygen plasma-treated graphene is modeled using a graphene sheet with adsorbed epoxide functional groups (C–O–C) on its one side. The most stable configurations of such oxidized graphene sheets with different O/C ratios ranging from 12.5% to 50% are then calculated. In the special case of O/C = 50% (fully oxidized surface), both single- and double-sided oxidation cases are considered. The elastic and electronic properties of the energetically most favorable configurations are evaluated under the tensile and compressive loads in harmonic range. For structures with high O/C ratios (O/C [Formula: see text] 25%), the elastic constants (modulus of elasticity and bulk modulus) are significantly smaller than those of graphene while for low O/C ratios (O/C [Formula: see text] 12.5%), these quantities are almost equal to the elastic constants of pristine graphene. We also found that the electronic bandgap of the oxidized sheets is increased under tensile loading.