Carrier-Concentration-Dependent Transport and Thermoelectric Properties of PbTe Doped with Sb₂Te₃

Abstract

The conversion of heat to electricity by thermoelectric (TE) devices may play a key role in the future for energy production and utilization. Lead telluride (PbTe) is one of the best TE materials used for TE generator in the medium temperature. In this report, the transport and TE properties of PbTe doped with antimony telluride (Sb₂Te₃), which has been used to optimize the carrier concentration for improved TE performance, have been studied. The scattering factor is estimated from the temperature-dependent Hall mobility and the results indicate that the scattering mechanism is changed from an ionized impurity scattering to the interaction between an acoustical and an optical phonon scattering as carrier concentration decreases and the temperature increases. The thermal conductivities for all the samples exhibit linearly dependence with reciprocal temperature and the slope increases with the carrier concentration increasing. The effective maximum power P_max for PbTe samples increases with an increase of carrier concentration when the temperature gradient is over 400 K and is comparable to the functional gradient materials with the same carrier concentration. This result indicates that high TE performance has been achieved in PbTe with Sb₂Te₃ as dopants.