Remarkably reduced thermal conductivity and enhanced thermoelectric properties of n-type PbTe via Sb and Cu co-doping

In this study, we demonstrate that co-doping Sb and Cu into n-type PbTe significantly enhances its thermoelectric performance by increasing electrical conductivity and reducing thermal conductivity at high temperatures. A series of Pb_1-2x (SbCu) _x Te (x = 0-0.006) samples were synthesized using a solid-state reaction method. The results show that the ZT values at 673 K range from 0.93 to 1.3, depending on the doping concentration. The maximum ZT value of 1.3 at 673 K was achieved for the sample with an optimal doping level of x = 0.005, attributed to the synergistic effects of Sb and Cu on carrier concentration optimization and enhanced phonon scattering. These findings provide a cost-effective and scalable approach to improving the thermoelectric efficiency of n-type PbTe, making it a promising candidate for mid-temperature thermoelectric applications.