Thermoelectric properties of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy with addition of BN and WO3 powders

Abstract

Thermoelectric properties of the (Bi0.2Sb0.8)(2)Te-3 alloy, fabricated by mechanical alloying and hot-pressing, were investigated with addition of BN and WO3 powders as phonon scattering centers. The Seebeck coefficient and the electrical resistivity of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy increased with increasing the volume fraction of BN and WO3. Although the thermal conductivity of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy decreased with increasing the volume fraction of BN and WO3 due to the reduction of kappa(e)l, the lattice thermal conductivity was not lowered. The figure-of-merit of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy, 3.05 x 10(-3)/K without addition of BN and WO3, decreased with increasing the volume fraction of BN and WO3, because the increment of the electrical resistivity was much larger than the decrement of the thermal conductivity due to the grain refinement. (C) 2000 Kluwer Academic Publishers.