Thermoelectric properties of nonstoichiometric PbTe prepared by HPHT

Although there has report on PbTe-based compounds with colossal improved thermoelectric (TE) performance by high pressure tuning, the high TE performance could not be kept to ambient pressure. In this report, nonstoichiometric PbTe sample with excess Pb (Pb0.55Te0.45) was prepared by high pressure and high temperature (HPHT) method and the temperature-dependent thermoelectric properties were studied. The absolute value of the Seebeck coefficient for the sample increases while the electrical conductivity and the thermal conductivity decrease with rising temperature. The maximum figure of merit, ZT, of 0.37 has been achieved at 690 K for this TE material.