Thermoelectric Properties of Nanocomposite Bi0.45Sb1.55Te2.985 Solid Solution with SiO2 Microparticles

Abstract

Nanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p-type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO₂ microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO₂ addition by almost 50% (at 300 K). When adding SiO₂, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.