Simultaneous enhancement in the power factor and thermoelectric performance of copper sulfide by In2S3 doping

Abstract

In this work, we demonstrate simultaneous enhancement of the power factor and thermoelectric performance of Cu₂S upon the introduction of In₂S₃. The evident improvement in electrical conductivity, coupled with the less affected Seebeck coefficient, leads to a high power factor of 1361 μW m⁻¹ K⁻² at 850 K, which is much higher than the previously reported values for Cu₂S-based thermoelectric materials. Along with moderate thermal conductivity, a high ZT value of 1.23 at 850 K is achieved. Interestingly, the phase transitions and copper segregation of Cu₂S are also suppressed by In₂S₃ doping due to the formation of the nanoscale CuInS₂ phase. Such a high power factor, together with a decent ZT value and suppressed phase transitions and copper segregation, will be beneficial to its practical applications in thermoelectric power generation.