Enhancing thermal boundary conductance of graphite-metal interface by triazine-based molecular bonding.

Thermal boundary conductance between graphite and metal plays an important role in developing thermally conductive composites and contacts for thermal managements. Based on the premise that the thermal boundary conductance (TBC) correlates with interfacial bonding strength, we conducted triazine-based molecular bonding process to improve interfacial adhesion forces between a-axis of highly oriented pyrolytic graphite and aluminum. The surface coverage of molecular bonding at the interface is estimated by the x-ray photoelectron spectroscopy and thermal boundary conductance is measured by the time-domain thermo-reflectance method. It is found that the TBC is directly proportional to the surface coverage of covalently bonded triazine linkers, with the proportionality constant for their increment rates being about unity. The experimental finding is supported by the corresponding simulation using the atomic Green's function method, which exhibits the same linear dependence on the surface coverage.