Enhanced thermoelectric performance of PbTe-based nanocomposites through element doping and SiC nanoparticles dispersion

Nanostructure is effective to improve thermoelectric performance by reducing the thermal conductivity. However, electrical conductivity is always synchronously deteriorated due to the scattering of charge carriers. Here, we introduce SiC nanoparticles into the matrix of Pb0.98Na0.02Te doped with SrTe. The two-phased heterostructure causes strong scattering of phonons with multiscale wavelengths, resulting in the decreased lattice thermal conductivity. The electrical conductivity is reduced while Seebeck coefficient is improved. As a result, a peak thermoelectric figure of merit (zT) of 1.73 with a calculated device efficiency of similar to 10.6% is achieved for the nanocomposites under the temperature range of 300-750 K. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.