Synergistically optimizing electrical and thermal transport properties of ntypePbSe

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_0.99Sb_0.01Se. 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_0.99Sb_0.01Se to ~ 2.9?Wm^?1 K^?1 (1.1?Wm^?1 K^?1) for Pb_0.99Sb_0.01Se-6%MgSe. Through combining Sb doping and Mg alloying, a maximum ZT of ~ 1.1 was achieved at 873?K for Pb_0.99Sb_0.01Se-6%MgSe, and the average ZT (ZT_ave) was increased by 28.6% from ~ 0.42 for Pb_0.99Sb_0.01Se to ~ 0.54 for Pb_0.99Sb_0.01Se-6%MgSe. The results indicate that PbSe is a robust candidate for medium-temperature thermoelectric applications.