Ab Initio Calculations of Nitrogen Functionalization of Graphene

Our collaboration between theorists and experimentalists aims to achieve nitrogen functionalization of graphene with the late-afterglow regime of a microwave plasma. We hope this technique will give us a better control on the functionalization due to the small density of interacting atoms in the late-afterglow and a drastic diminution of induced defects compared to standard plasma functionalization techniques. Using software packages ABINIT and BigDFT, we carried out first-principles calculations to study many different interactions possible between nitrogen atoms and graphene, both in-plane and on top of the sheet. Formation energies were obtained and compared to obtain insights into the configurations importance and stability. In order to understand the doping process at the atomic scale, we used the Nudged Elastic Band method to calculate energy barriers for different diffusion and absorption paths for adsorbed nitrogen atoms.