The effect of secondary phase on thermoelectric properties of Zn4Sb3 compound

Zn4Sb3 is a promising thermoelectric material because of its high thermoelectric performance and the abundance of Zn and Sb in nature. Samples of Zn4Sb3 with ZnSb or Zn as the minor phase were prepared to optimize the figure-of-merit (ZT). The effects of ZnSb or Zn secondary phase on the thermoelectric properties of Zn4Sb3 were investigated. The highest peak ZT of about 1.2 was achieved at 400 degrees C in the sample with single Zn4Sb3 phase, which has the lowest thermal conductivity. Transmission electron microscopy observations of the nanostructures suggest that the precipitated ZnSb, Zn-rich nanoparticles, and nanovoids, caused by volatile Zn diffusion, all contribute to the extraordinarily low thermal conductivity. (C) 2013 Elsevier Ltd. All rights reserved.