Thermal boundary resistance of copper phthalocyanine-metal interface

Systems containing interfaces between dissimilar materials can exhibit lower thermal conductivity than their pure constituents, with important implications for thermal management and thermoelectric energy conversion. However, the heat transfer processes at such interfaces, in particular those between organic and inorganic materials, remain for the most part uncharacterized. We use vacuum thermal evaporation to grow archetypal multilayer thin films of copper phthalocyanine (CuPc) and Ag or Al, and measure their thermal conductivity as a function of interface density. We observe large thermal boundary resistance values ($7.8\times {10}^{-8}{\text{m}}^2\text{K}/\text{W}$ for CuPc/Ag and $2.0\times {10}^{-8}{\text{m}}^2\text{K}/\text{W}$ for CuPc/Al), attributable to acoustic mismatch, heat carrier mismatch, and weak bonding.