Enhanced thermoelectric performance of n-type Bi2S3 with added ZnO for power generation

Abstract

Although Bi₂S₃ is one of the promising thermoelectric materials, its practical application is limited by a relatively low dimensionless figure of merit (ZT), and especially low electrical conductivity. In this work, ZnO was used to tune the thermal and electrical properties of Bi₂S₃. In the preparation processes of mechanical alloying (MA) and spark plasma sintering (SPS), small amounts of ZnO converted to ZnS in the sulfur rich environment, accompanied by the production of sulfur vacancies and micro/nanostructures. The sulfur vacancies increased the electrical conductivity of n-type Bi₂S₃ and micro/nanostructures scattered phonons without commonly deteriorating electronic transport. The maximum ZT value of 0.66 at 675 K for Bi₂S₃ doped with 1.0 mol% ZnO was obtained and the results of this work perhaps provide a new way for designing and fabricating thermoelectric materials.