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

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 Bi 0.48 Sb 1.52 Te 3 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 κ l 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.