Characterizations of solid-state microwave-synthesized Sb2Te3-based alloys with various compositions of bismuth in Bi2xSb2(1-x)Te3

In this article, thermoelectric (TE) materials based on p-type Sb2Te3 samples and dispersed with x amounts of Bi (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) in the form Bi2Sb2(1-x)Te3 were synthesized via a standard solid-state microwave route. The microstructure of the ingots was characterized by field emission scanning electron microscopy. As-synthesized ingots were formed by the assembly of micro-sheet grains. The phase composition of the powders was characterized by X-ray diffraction, revealing a rhombohedral structure. The influence of variations in Bi content (x) on the TE properties of the resulting alloy was studied in the temperature range of 303 K to 523 K. Increases in x caused a decrease in hole concentration and electrical conductivity and an increase in Seebeck coefficient. A maximum power factor of 4.96 mW/mK(2) was obtained at about 373 K for a Bi2xSb2(1-x)Te3 sample with x=0.2. (C) 2012 Elsevier Ltd. All rights reserved.