Preparation of graphene/copper composites with a thiophenol molecular junction for thermal conduction application

Abstract

Elimination of interfacial thermal resistance is a critical issue to improve the thermal conductivity of graphene-based metal matrix composites. Here, thiophenol groups were employed to construct an interfacial molecular junction between graphene and copper to improve the thermal conduction performance of the graphene/copper composite. The highly delocalized aryl properties of thiophenol groups can facilitate electron tunneling at the interface, thereby increasing the electron thermal conduction and reducing the interfacial thermal resistance between graphene and copper nanoparticles. The resulting thiophenol group linked graphene and copper composite shows a high thermal conductivity of 500.6 W m⁻¹ K⁻¹, which is 1.43 and 1.30 times higher than those of copper (Cu) and pristine graphene–copper composites (Gr–Cu), respectively, and also higher than most reported values via a single phonon thermal conduction route. Placed on a heat source heated from 26 °C to 213 °C within 5 min, the top surface temperature of TP–Gr–Cu increases to 184.2 °C rapidly, whereas those of Gr–Cu and Cu only increase slowly to 61.4 °C and 51.6 °C. This work demonstrates that an interfacial electron thermal conduction route can be built through electron tunneling by constructing a molecular junction between graphene and copper, which can significantly reduce the interfacial thermal resistance and improve the interfacial thermal conductivity.