Thermoelectric Performance of Single Phase p-Type Quaternary (PbTe)(0.65-x)(PbSe)(0.35)(PbS)(x) Alloys
Recently, the quaternary system PbTe−PbSe−PbS has been shown to provide highthermoelectric efficiency,zT. The intent of this research is to investigate the thermoelectric propertiesof Na-doped pseudoternary (PbTe)0.65−x(PbSe)0.35(PbS)xwith a high ratio of PbS to PbTe. Theaddition of a large concentration of PbSe increases the solubility limit of PbS in PbTe, allowing allsamples to behave as solid solutions with a high concentration of PbS. This is proven to decrease latticethermal conductivity due to the larger atomic mass contrast between sulfur and tellurium; however, itsimultaneously causes a decrease in the Seebeck coefficient due to a larger band offset, so a highconcentration of PbS shows no improvement inzT, with a maximum of∼1.4 in thex= 0, 0.05, and 0.10 samples.