Enhanced thermoelectric and mechanical properties of zone melted p-type (Bi,Sb)2Te3 thermoelectric materials by hot deformation

Zone-melted bismuth antimony telluride alloys have been the most widely applied commercial thermoelectric (TE) materials for decades. In this work it is demonstrated that hot deformation can enhance both TB properties and mechanical properties of zone-melted (Bi,Sb)(2)Te-3 alloys. The hot deformation modifies the microstructure and induces a donor-like effect to adjust the carrier concentration and significantly reduce the lattice thermal conductivity. A high dimensionless figure of merit (ZT) of 1.36 at 400 K is obtained in Bi0.4Sb1.6Te3 after hot deformation, and also the average ZT is similar to 1.2 in the temperature range of 300-525 K, which makes the alloy suitable for low temperature power generation. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.