Thermoelectric properties of (Bi0.25Sb0.75)(2)Te-3 prepared by mechanical alloying and hot pressing

Abstract

The thermoelectric properties of polycrystalline (Bi0.25Sb0.75)(2)Te-3 fabricated by mechanical alloying and hot pressing have been investigated. (Bi-0.25 Sb-0.75)(2)Te-3 was formed by mechanical alloying of elemental Pi, Sb, and Te granules for 5 hours at ball-to-material weight ratio of 5:1. The figure-of-merit of (Bi0.25Sb(0.75))(2)Te-3, measured at 300 K, increased from 0.93x10(-3)/K to 2.8x10(-3)/K with increasing hot-pressing temperature from 300 degrees C to 550 degrees C. Optimization of the figure-of-merit (similar to 3.0x10(-3)/K) could be achieved by a compositional change to (Bi0.2Sb0.8)(2)Te-3 lather than by impurity doping to (Bi0.25Sb0.75)(2)Te-3.