First principles studies of the graphene-phenol interactions.

Studies of the interaction between phenol and intrinsic graphene, as well as phenol and aluminum doped graphene layer are performed using first principles total energy calculations within the periodic density functional theory. A 4x4 periodic structure is used to explore the adsorption of a phenol molecule on the intrinsic graphene and on aluminum doped graphene layer. The electron-ion interactions are modeled using ultra-soft pseudo-potentials, and the exchange-correlation energies are treated according to the generalized gradient approximation (GGA) with the PBE parameterization. We consider different molecule orientations: parallel and perpendicular to the graphene layer to relax the atomic structure. To explain the optimized atomic geometry we determine binding energies for all cases and the density of states (DOS) and partial DOS for the most relevant configurations. Results indicate that the direct interaction of oxygen with aluminum yields the ground state geometry with the phenol molecule adsorbed on the graphene layer. Binding energies and DOS structures also demonstrate that the ground state configuration is that where the O and Al atoms interact with a separation distance of 1.97 Å.