Thermoelectric Properties of PbS Doped with Bi2S3 and Cu2S Prepared by Hydrothermal Synthesis and Spark Plasma Sintering

Abstract

Hierarchical PbS powders doped with different contents of Bi2S3 and Cu2S were synthesized using the hydrothermal method. Subsequently, the powders were subjected to spark plasma sintering (SPS) for consolidation into bulk ceramics. X-ray photoelectron spectroscopy results showed that Bi2S3 and Cu2S were doped into PbS successfully. The effect of doping with different Bi2S3 and Cu2S contents on thermoelectric performance was investigated systematically. The results showed that pure PbS was an n-type semiconductor, and Bi2S3 doping or Bi2S3-Cu2S co-doping could decrease the thermal conductivity of PbS effectively. PbS doped with 1% Bi2S3 exhibited a moderate Seebeck coefficient, high electric conductivity, and low thermal conductivity simultaneously, thus attaining a maximum figure of merit ZT of 0.55 at 773 K. PbS doped with 1% Bi2S3-1% Cu2S exhibited an enhanced power factor and reduced thermal conductivity at an elevated temperature; the maximum ZT value obtained at 773 K was 0.83, which is more than twice that of pure PbS at 758 K (0.29), as a result.