Effect of high pressure sintering on the thermoelectric properties of n-type PbTe

The n-type nonstoichiometric PbTe (Pb 0.55Te 0.45) materials were prepared by the high pressure sintering process. The emphasis of the present study is on the influence of the pressure on the thermoelectric properties of the material. The experimental results show that the lattice defects are removed by high pressure sintering process, and it effectively adjusts the carrier concentration and its transport properties. Compared with the melting ingots, the Seebeck coefficient of the high pressure sintering sample obtains enhancement largely, the electric conductivity slightly reduces, simultaneously the thermal conductivity is low, and therefore the figure of merit (Tα 2σ/κ) of the high pressure sintering sample is greatly enhanced. Therefore, the maximum the figure of merit of the sample prepared by 2 GPa reaches 0.59 at 700 K, which is about 150% improvement in comparison with the melting ingot.