Low-temperature thermoelectric properties of Bi85Sb15−xNbx alloys prepared by high-press sintering

The nanocrystalline materials with the general formula Bi85Sb15−xNbx (x=0, 0.5, 1, 2, 3) were prepared by mechanical alloying and subsequent high-pressure sintering. Their transport properties involving electrical conductivity, Seebeck coefficient and thermal conductivity have been investigated in the temperature range of 80–300 K. The absolute value of Seebeck coefficient of Bi85Sb13Nb2 reaches a maximum of 161 μV/K at 105 K, which is 69% larger than that of Bi85Sb15 at the same temperature. The power factor and figure-of-merit are 4.45×10−3 WK−2m−1 at 220 K and 1.79×10−3 K−1 at 196 K, respectively. These results suggest that thermoelectric properties of Bi85Sb15 based material can be improved by Nb doping.