Enhanced thermoelectric performance in n-type polycrystalline SnSe by PbBr2 doping

Abstract

A series of PbBr₂-doped polycrystalline SnSe samples were synthesized by melting and hot pressing. By PbBr₂ doping, the carrier concentration of SnSe was increased to 1.86 × 10¹⁹ cm⁻³ from 2.41 × 10¹⁷ cm⁻³, resulting in an increased electrical conductivity of 40 ± 2 S cm⁻¹ at 713 K while the undoped SnSe was only 5.1 ± 0.3 S cm⁻¹. Meanwhile, the PbBr₂-doped samples also exhibit a larger density of state effective mass (0.812m₀). Therefore, a high power factor of 4.8 ± 0.5 μW cm⁻¹ K⁻² and a peak ZT of 0.54 ± 0.1 were achieved at 793 K perpendicular to the hot pressing direction.