An approach of enhancing thermoelectric performance for p-type PbS: Decreasing electronic thermal conductivity

In this work, the thermoelectric performance of p-type PbS was boosted remarkably through Na doping and introducing Cu2S. Firstly, the electrical transport properties (power factor) of p-type PbS was optimized via Na doping, and the maximum ZT similar to 0.67 was achieved in Pb0.98Na0.02S. Secondly, the total thermal conductivity of Pb0.98Na0.02S was suppressed through introducing Cu2S by means of significantly reducing the electronic thermal conductivity by 80% at 823 K through Cu counter-doping, meanwhile, the power factor of Pb0.98Na0.02S was further enhanced through optimizing carrier concentrations via introducing Cu. The combination of decreasing total thermal conductivities and the optimizing power factors leads to peak ZT similar to 1.2 at 823 K in p-type PPb0.98Na0.02S-2%Cu2S. Present results illustrate that introducing Cu2S is an effective method to enhance the thermoelectric performance of p-type PbS through decreasing the electronic thermal conductivity which also has great potential in other thermoelectric materials system. (C) 2019 Elsevier B.V. All rights reserved.