Effect of Nanopowders Addition on the Thermoelectric Properties of n-Type Bi2Te3 Nanocomposites

Bi2Te3 nanopowders with an average grain size of about 40 nm were synthesized by vacuum arc plasma evaporation. The n-type bulk Bi2Te3 nanocomposites were prepared by consolidating the mixtures of these nanopowders and mechanically alloyed powders using plasma activated sintering, and the effect of the addition of nanopowders on the thermoelectric properties of bulk Bi2Te3 nanocomposites was investigated. With increasing the content of the added nanopowders, the electrical resistivity and Seebeck coefficient of the nanocomposites increased and the thermal conductivity decreased. When the content of the added nanopowders was 20 wt%, the thermal conductivity decreased by 21.4% compared with that of the nanopowders-free compounds. A preliminary investigation showed that the addition of nanopowders was an effective way to decrease the thermal conductivity and increase the thermoelectric efficiency.