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–Cu2SnTe3nanocomposites with a homogeneous phase distribution
by decomposing the liquid SnTe precursor containing a dispersion of
Cu1.5Te colloidal nanoparticles. The presence of Cu within
the SnTe and the segregated semimetallic Cu2SnTe3phase 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–1K–2and thermoelectric figures
of merit up to 1.04 are obtained at 823 K, which represent a 167%
enhancement compared with pristine SnTe.