Substrate-Induced Interfacial Coupling between Graphene and Copper.

Graphene/copper (Gr/Cu) composites, which combine the exceptional electrical, thermal, and mechanical properties of both components, have emerged as a promising platform for advanced electronic and energy storage applications. Successful studies have been done on optimizing graphene incorporation and morphology, while the impact of Gr/Cu interfacial interactions on composite performance remains underexplored. Here, we systematically investigate eight Gr/Cu interfaces and clarify their interfacial coupling relationships. Our results demonstrate that the doping level of graphene closely correlates with the crystallographic orientation of Cu, where Gr/Cu(111) exhibits the highest electron doping level, and Gr/Cu(332) shows the lowest. Higher doping is accompanied by greater graphene surface friction, revealing a direct link between charge transfer at the interface and tribological behavior. Crystallographic orientation control represents an atomically precise interfacial engineering strategy for tailoring interfacial coupling. Through this approach, charge transfer and friction can be effectively tuned, paving the way for the rational design of high-performance Gr/Cu composites for applications such as efficient power transmission, reliable electrical interconnects, and low-friction systems.