Effect of Na and Ba co-doping on the structure and thermoelectric performance of PbTe0.5Se0.5

PbTe-based semiconductor thermoelectric materials are currently active areas of research. In this work, Na- and Ba-doped PbTe0.5Se0.5 alloys were prepared by vacuum melting and spark plasma sintering techniques. Na doping suppressed the transition of PbTe0.5Se0.5 from p-type to n-type conductivity and adjusted the carrier concentration. In the case of Na0.02(BaxPb1−x)0.98Te0.5Se0.5, doping with Ba increased the Seebeck coefficient, decreased the thermal conductivity, and improved the thermoelectric performance compared to those of the undoped material. A high figure of merit (ZT) value of 1.17 at 723K was obtained for Na0.02(Ba0.06Pb0.94)0.98Te0.5Se0.5, which is approximately 22% greater than that of the undoped sample. [Display omitted]