In Situ Nanostructure Generation and Evolution within a Bulk Thermoelectric Material to Reduce Lattice Thermal Conductivity

We show experimentally the direct reduction in lattice thermal conductivity as a result of in situ nanostructure generation within a thermoelectric material. Solid solution alloys of the high-performance thermoelectric PbTe-PbS 8% can be synthesized through rapid cooling and subsequent high-temperature activation that induces a spontaneous nucleation and growth of PbS nanocrystals. The emergence of coherent PbS nanostructures reduces the lattice thermal conductivity from similar to 1 to similar to 0.4 W/mK between 400 and 500 K.