Enhanced thermoelectric performance of Bi2S3 by synergistical action of bromine substitution and copper nanoparticles

In our work, CuBr2 doping could remarkably enhance the thermoelectric performance of Bi2S3. Cu intercalation and Br substitution at sulfur sites contribute to a sharp decrease of electrical resistivity. Simultaneously, the strong point defects caused by Br alloying and formed Cu nanoparticles noticeably suppress the thermal conductivity. Collectively, the maximum ZT of 0.72 at 773 K and average ZT of 0.40 from 300 K to 773 K is obtained for the 0.5 mol% CuBr2 doped sample, making it a very robust candidate among the thermoelectric sulfides in the medium temperature range.277