Bottom-Up Synthesis of SnTe-Based Thermoelectric Composites.

There is a need for the development of lead-free thermoelectric materials for medium-/high-temperature applications. Here, we report a thiol-free tin telluride (SnTe) precursor that can be thermally decomposed to produce SnTe crystals with sizes ranging from tens to several hundreds of nanometers. We further engineer SnTe-CuSnTe nanocomposites with a homogeneous phase distribution by decomposing the liquid SnTe precursor containing a dispersion of CuTe colloidal nanoparticles. The presence of Cu within the SnTe and the segregated semimetallic CuSnTe phase effectively improves the electrical conductivity of SnTe while simultaneously reducing the lattice thermal conductivity without compromising the Seebeck coefficient. Overall, power factors up to 3.63 mW m K and thermoelectric figures of merit up to 1.04 are obtained at 823 K, which represent a 167% enhancement compared with pristine SnTe.