Synergistically optimizing electrical and thermal transport properties of n-type PbSe

In this paper, we report that the thermoelectric performance of n -type PbSe could be improved through synergistically optimizing electrical and thermal transport properties via Sb doping and Mg alloying. The carrier concentration was firstly optimized through Sb doping, resulting in a maximum power factor of ~ 15.4 μW cm −1 K −2 and maximum ZT of ~ 0.9 at 873 K in Pb 0.99 Sb 0.01 Se. Then, Mg was selected for alloying in Pb sites to produce point defects, which can largely intensify the phonon scattering and lower thermal conductivity. After Mg alloying, the thermal conductivity at 300 K (873 K) was significantly suppressed from ~ 4.6 Wm −1 K −1 (1.5 Wm −1 K −1 ) for Pb 0.99 Sb 0.01 Se to ~ 2.9 Wm −1 K −1 (1.1 Wm −1 K −1 ) for Pb 0.99 Sb 0.01 Se-6%MgSe. Through combining Sb doping and Mg alloying, a maximum ZT of ~ 1.1 was achieved at 873 K for Pb 0.99 Sb 0.01 Se-6%MgSe, and the average ZT ( ZT ave ) was increased by 28.6% from ~ 0.42 for Pb 0.99 Sb 0.01 Se to ~ 0.54 for Pb 0.99 Sb 0.01 Se-6%MgSe. The results indicate that PbSe is a robust candidate for medium-temperature thermoelectric applications.