Thermoelectric properties of 25%Bi 2Te 3-75%Sb 2Te 3 solid solution prepared by hot-pressing method

Abstract

The Seebeck coefficient and electrical conductivity of the 25%Bi 2Te 3-75%Sb 2Te 3 solid solution prepared by hot-pressing method were measured and the effects of particle size, oxidation, hot-pressing temperature and time on the Seebeck coefficient of the polycrystalline solid solution were examined in detail. It has been found that the mechanical deformation during pulverization or pressing processes is very important in controlling the Seebeck coefficient. The role of the anion vacancies formed by the mechanical deformation as well as the change of the antistructure defect concentration were discussed. By optimizing particle size and hot-pressing temperature, the figure of merit about 2.9 x 10 −3 K −1 could be obtained for the P-type polycrystalline 25%Bi 2Te 3-75%Sb 2Te 3 solid solutions without excess Te addition.