ZnTe Alloying Effect on Enhanced Thermoelectric Properties of p-Type PbTe

We investigate the effect of ZnTe incorporation on PbTe to enhance thermoelectric performance. We report structural, microscopic, and spectroscopic characterizations, ab initio theoretical calculations, and thermoelectric transport properties of Pb 0.985 Na 0.015 Te– x % ZnTe ( x = 0, 1, 2, 4). We find that the solid solubility limit of ZnTe in PbTe is less than 1 mol %. The introduction of 2% ZnTe in p-type Pb 0.985 Na 0.015 Te reduces the lattice thermal conductivity through the ZnTe precipitates at the microscale. Consequently, a maximum thermoelectric figure of merit ( ZT ) of 1.73 at 700 K is achieved for the spark plasma-sintered Pb 0.985 Na 0.015 Te–2% ZnTe, which arises from a decreased lattice thermal conductivity of ∼0.69 W m –1 K –1 at ∼700 K in comparison with Pb 0.985 Na 0.015 Te.