Achieving higher thermoelectric performance of n-type PbTe by adjusting the band structure and enhanced phonon scattering.

Due to the very distinct electronic band structure and lower power factor, the exploration of n-type PbTe as thermoelectric materials has historically fallen behind that of p-type PbTe. In this work, n-type PbSbTe-based composites incorporated with CuSbS nanoparticles are synthesized and investigated. Sb doping is utilized to modify its carrier concentration in order to obtain n-type PbTe materials with a high power factor. Then, the incorporation of CuSbS nanoparticles can generate semi-coherent nanophase CuTe, and simultaneously optimize the thermal and electrical properties due to remarkable energy filtering effects and interface scattering in the higher temperature range. Eventually, a peak figure of merit ZT ≈ 1.58 was obtained at 773 K for the sample PbSbTe + 1.5 wt% CuSbS, indicating that the incorporation of CuSbS in PbSbTe is an effective approach to improve its thermoelectric performance.