Macroscopic thermoelectric efficiency of carbon nanocomposites

The subject of this study is the thermoelectric efficiency $(Z)$ and the thermoelectric parameter $(ZT)$ of carbon nanocomposites, namely, the structures consisting of graphite-like $(gr)$ and diamond-like $(d)$ regions made of $sp^2$ and $sp^3$ hybridized carbon atoms, respectively. The impact of heat transfer across the boundary between $sp^2$ and $sp^3$ areas is analyzed for the first time. It is shown that the interfacial thermal resistance (Kapitza resistance) is not lower than the thermal resistance in the macroscopic gr region. The influence of various factors on the Kapitza resistance is analyzed. The value of $ZT\approx3.5$ at room temperature, taking into account the interfacial thermal resistance, is significantly higher than it would be in $gr$ films $(ZT\approx0.75)$.