Vacant defect and nitrogen doping effects on the interface of graphene/Cu composites: Computational and experimental evaluation

Abstract

To explore an efficient way of modifying carbon nanomaterials to improve the interfacial bonding with the Cu matrix, the interaction between Cu and pristine graphene, single- and double-vacant defect graphene, and nitrogen-doped graphene was systematically investigated by density functional theory (DFT) calculations. The electronic structure, including Bader charge and charge density differences, reveals that the existence of vacancies and nitrogen doping are beneficial for the transfer of electrons at the interface, mainly due to the enhanced binding energy and their intense interaction with Cu atomic orbitals. Pyridine-N and pyrrole-N are more capable of coupling with the interfacial Cu atoms, suggests a vital role of nitrogen doping in the improvement of the mechanical and electrical properties of graphene/Cu composites. To validate our computational prediction, heat-treated carbon polymer dot (CPD), which can be regarded as nitrogen-rich graphene, were employed to prepare bulk CPD/Cu composites. The mechanical performance was significantly better than that of the pure Cu matrix, proves that nitrogen doping could effectively improve C/Cu interface bonding. This research provided a theoretical and experimental basis for the preparation of advanced Cu matrix composites. • The interaction between Cu and graphene was investigated by DFT calculation. • The existence of vacancies and nitrogen doping is beneficial for transferring electrons at the interface. • Pyridine-N and pyrrole-N are more capable for coupling with the interfacial Cu atoms. • The heat-treated CPD is employed to prepare bulk CPD/Cu to verify the calculated results. • The mechanical performances are better than that of pure Cu matrix.