Synergistically Optimized Thermoelectric and Mechanical Properties in p‐Type BiSbTe by a Microdroplet Deposition Technique

Abstract

Bismuth telluride is widely used in thermoelectric cooling, but the commercial zone‐melting materials suffer the poor mechanical property and dramatically decrease thermoelectric performance at intermediate temperature. Herein, a low‐cost and high‐efficiency preparation technique named microdroplet deposition is demonstrated to synergistically improve the thermoelectric and mechanical properties of Bi0.48Sb1.52Te3 alloy. It is found that a weakly preferred alignment with fine grains occurs during the molten droplets flattening and stacking processes. Although the obtained power factor is not further improved, the corresponding κl is significantly suppressed due to the increased interfacial thermal resistance between flakes by the micropores and dense grain boundaries. Consequently, a peak ZT of 1.12 and a Vickers hardness of 0.60 GPa are simultaneously achieved in the microdroplet‐deposited sample.