Bi0.33(Bi6S9)Br compositing in Bi2S3 bulk materials forwards high thermoelectric properties

The hexagonal Bi0.33(Bi6S9)Br intermediate was incorporated to enhance the thermoelectric properties of Bi2S3 by a facile synthesis process. As a result of the increase of carrier concentration caused by Br diffusion doping and the enhancement of phonon scattering caused by pores, point defects, and secondary phase interfaces, a maximum ZT value of 0.64 was achieved at 773 K in Bi2S3 + 5% Bi0.33(Bi6S9)Br. This study provides a strategy for achieving Br doping in the Bi2S3 system by adding the Bi0.33(Bi6S9)Br intermediate alloy, while the nanostructure was maintained in the matrix, which may be also suitable for other thermoelectric materials to obtain higher performance.