Improved thermoelectric properties of zone‐melted p‐type bismuth‐telluride‐based alloys for power generation

Abstract

Zone‐melted bismuth‐telluride‐based alloys (ZM‐BT) are extensively applied to manufacture commercial thermoelectric power generators (TEG). Optimizing the average figure of merit ( zT ) during 300–500 K of ZM‐BT is favorable for improving the conversion efficiency of common TEGs, and manipulating point defects is the primary approach to reduce their relatively high lattice thermal conductivity ( κ l ) and enhance thermoelectric properties further. Se/Te alloying has been confirmed effective for traditional n‐type Bi 2 Te 3 compound, while Se alloying in p‐type counterparts is rarely reported. Herein, to further reduce κ l , we introduce Se alloying into p‐type Bi 0.3 Sb 1.7 Te 3 to enhance the scattering of high‐frequency phonons. Combined with the carrier concentration adjustment via excess Te doping, a high average zT ~ 0.75 between 300 and 500 K was obtained, 22% higher than that of the pristine ingot.