First-principles prediction of enhancing graphene/Al interface bonding strength by graphene doping strategy

In this research work, first-principles calculation method is performed to investigate the effects of atomic doping in graphene on the graphene/Al interface bonding properties. It is found that the bonding strength of Al(1 1 1)/perfect graphene/Al(1 1 1) interface is extremely weak (only 0.063 J/m(2)) due to the limited charge redistribution on the interface. The atomic doping (including N-doping, B-doping and B-N co-doping) in graphene could obviously enhance the Al(1 1 1)/graphene/Al(1 1 1) interface bonding strength with more than ten times, the improvement effect increases with the enhancement of doping concentration and the N-B co-doping in graphene has the best improvement effect at the same doping concentration. The reason why the N-doping or B-doping in graphene could obviously enhance the interface bonding strength is that the doped atom could cause the pronounced hybridization between a more delocalized Al-3p states and the 2p states of both the doped atoms and their neighboring C atoms. For the N-B co-doping case, more specifically, the strong interaction between the doped-N and doped-B atoms could weaken the interactions of their neighboring C atoms, resulting in the further enhancement of interaction between interfacial Al atoms and C atoms neighboring the doped atom. This study could provide an efficient way of modifying the graphene/Al interface to improve the mechanical properties of graphene/Al composites.