THERMOELECTRIC PROPERTIES OF 25-PERCENT-BI2TE3-75-PERCENT-SB2TE3 SOLID-SOLUTION PREPARED BY HOT-PRESSING METHOD

The Seebeck coefficient and electrical conductivity of the 25% Bi2Te3 - 75 % Sb2Te3 solid solution prepared by hot-pressing method were meas ured and the effects of particle size, oxidation, hot-pressing tempera ture and time on the Seebeck coefficient of the polycrystalline solid solution were examined in detail. It has been found that the mechanica l deformation during pulverization or pressing processes is very impor tant in controlling the Seebeck cofficient. The role of the anion vaca ncies formed by the mechanical deformation as well as the change of th e antistructure defect concentration were discussed. By optimizing par ticle 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% Bi2 Te3 - 75% Sb2Te3 solid solutions without excess Te addition. (C) 1997 Elsevier Science Ltd.