First-principles Studies of CO 2and NH 3 Gas Molecules Adsorbed on Graphene Nanoribbons

Abstract

We present first-principles studies of CO2and NH3 adsorbed on graphene nanoribbons (GNRs). The electronic and transport properties are calculated based on density functional theory combined with non-equilibrium Green's function method. Absorption energy, density of states, electron density deformation, charge transfer, current-voltage characteristics, and transmission spectra were analyzed. It is found that CO2and NH3adsorbed on GNRs exhibit acceptor-like and donor-like behaviors, respectively. Both CO 2and NH3 molecules show physissorption on GNRs with low adsorption energiesand small charge transfers. In other words, the interactions between CO2and NH3 molecules and GRNs are very weak. The results suggest that the sensitivity and selectivity of GRN-based gas sensors could be improved by introducing the dopant, defect, or modification of electronic structures of graphene