Highly enhanced thermoelectric properties of Bi2S3 via (Se, Cl)-co doping in hydrothermal synthesis process

Bi2S3-based materials with low thermal conductivity and high Seebeck coefficient has been regarded as promising thermoelectric materials for years. To optimize the thermoelectric properties of Bi2S3 materials, (Se, Cl)-co-doped nanostructured Bi2S3 bulks were prepared by hydrothermal method combined with spark plasma sintering. The doping contents of Se and Cl in Bi2S3 depend on the reaction time of the hydrothermal process. A high power factor of 450 mu Wm(-1) K-2 was achieved for Bi2S3 sample with the reaction time of 24 h owing to the substitution of S by Se and Cl. Meanwhile, a low thermal conductivity of 0.35 Wm(-1) K-1 is obtained for the Bi2S3 sample with the reaction time of 18 h, owing to the strong phonon scattering caused by the high density of grain boundaries, pores and point defect. Therefore, benefiting from the improved electrical transport properties and reduced thermal conductivity, a peak ZT value of similar to 0.57 was obtained at 673 K for the Bi2S3 sample with the reaction time of 24 h. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

Low thermal conductivity and high Seebeck coefficient have made Bi2S3-based materials promising for thermoelectric applications. By co-doping with Se and Cl, nanostructured Bi2S3 bulks were prepared, leading to improved power factor and reduced thermal conductivity. As a result, the Bi2S3 samples exhibited enhanced thermoelectric efficiency at high temperatures.