Band Engineering for Realizing Large Effective Mass in Cu₃SbSe₄ by Sn/La Codoping

Abstract

How to further improve the thermoelectric performance in Cu3SbSe4-based materials after optimizing its carrier concentration is a difficult issue. The present study attempts to address the issue by investigating thermoelectric performance of Cu3SbSe4 after Sn and La codoping, and all the samples were obtained by using a microwave-assisted hydrothermal synthesis method followed with the spark plasma sintering (SPS) process. First, a series of Cu3Sb1–xSnxSe4 (x = 0–0.03) compounds have been synthesized, and the hole carrier concentration obviously increased with increasing the Sn content. In addition, La doping subsequently was employed to the Cu3Sb0.98Sn0.02Se4 sample to further increase its power factor by band flattening, resulting in a typical high power factor of 1156.5 μWm–1 K–2 and zT of 0.67 in Cu3Sb0.92Sn0.02La0.06Se4 at 623 K. Our study provides a novel methodology through regulating its carrier concentration and band structure for designing high thermoelectric performance Cu3SbSe4-based materials.