Enhanced heat spreader based on few-layer graphene intercalated with silane-functionalization molecules

We studied the heat-spreading enhancement of supported few-layer graphene by inserting silane-functionalization molecules between graphene sheets. We calculated the overall thermal resistance of graphene-substrate interface and the in-plane thermal conductivity of graphene sheets by equilibrium molecular dynamics simulations. We probed the spectral phonon transmission coefficient by non-equilibrium Green´s function to characterize the local heat conduction through the interface. Our results show that the overal thermal resistance between the substrate graphene and the upper two-layer graphene underwent a three-fold increase by the presence of the molecules, while the local heat conduction from the hot spot to the graphene sheets through the molecules was largely intensified. Furthermore, the in-plane thermal conductivity of the few-layer graphene increased by 60% compared with the supported graphene non-bonded to the substrate through the molecules. This increase is attributed to the refrained cross-plane phonon scattering which in turn reinforces the in-plane heat conduction of the few-layer graphene. In summary, we proved that by inserting silane-functionalization molecules, the few-layer graphene becomes an ideal candidate for heat spreading by guiding heat more efficiently away from the heat source.