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

Abstract

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 Pb_0.97Sb_0.03Te-based composites incorporated with Cu₁₂Sb₄S₁₃ 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 Cu₁₂Sb₄S₁₃ 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 Pb_0.97Sb_0.03Te + 1.5 wt% Cu₁₂Sb₄S₁₃, indicating that the incorporation of Cu₁₂Sb₄S₁₃ in Pb_0.97Sb_0.03Te is an effective approach to improve its thermoelectric performance.