Grain Size Effect on the Figure of Merit of Sintered Solid Solutions Based on Bi2Te3

The dependence of the thermoelectric figure of merit Z on grain size in sintered 16% Bi2Se3-84% Bi2Te3 and 75% Sb2Te3-25% Bi2Te3 solid solutions is analysed. In n-type materials, due to the carrier density dependence on the specific surface, the maximum moves towards large grain sizes when doping increases. In p-type materials, the changes of Z with grain size are smaller than in n-type materials.