Effects of La doping induced carrier concentration regulation and band structure modification on thermoelectric properties of PbSe

Abstract Here, we have systematically explored the effects of rare-earth metal La doping on the thermoelectric properties of PbSe. The results show that i) La is an effective n-type dopant to regulate the carrier concentration, ii) La-doping can flatten the conduct band of PbSe to increase the effective mass and thus the improved Seebeck coefficient. Under the combined regulation of carrier concentration and band structure, a high average power factor of 1650 µW.m−1K−2 among 300-873 K is obtained. Meanwhile, the lattice thermal conductivity will be reduced due to the extra point defect scattering and the depressed bipolar conduct by La doping. Finally, a peak ZT of 0.96 and a high average ZT of 0.71 among 300-873 K are achieved in the 0.125% La doped sample. The multiple beneficial effects stemming from rare-earth metal La doping is an important finding that will stimulate new exploration toward high-performance n-type PbSe-based thermoelectric materials.