Thermoelectric Properties of P-Type PbTe Prepared by High Pressure

PbTe is the only thermoelectric material that has been commercially used for power generation in the medium temperature. It has been found that the n-type PbTe with high performance can be synthesized by high pressure method, but so far there has been no report on similarly prepared p-type PbTe, which is also needed for the application of thermoelectric materials. In this study, we successfully synthesized PbTe with an excess of Te using the high pressure method, and studied their thermoelectric properties at room temperature. It turns out that the main carriers of PbTe with 6% excess Te are holes, indicating that they are p-type semiconductors. By changing the content of Te, we optimized the electrical transport properties of PbTe and decreased their thermal conductivities. The maximum figure-of-merit, 0.21, was obtained for p-type PbTe_1.12, which is about 50% higher than that of PbTe with standard stoichiometric ratio synthesized by the same method. All the results show that the high pressure method, combined with the adjustment of the stoichiometric ratio, can prepare p-type PbTe thermoelectric materials that possess high thermoelectric performance.