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 ∼ 0.67 was achieved in Pb_0.98Na_0.02S. Secondly, the total thermal conductivity of Pb_0.98Na_0.02S 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 Pb_0.98Na_0.02S 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 ∼1.2 at 823 K in p-type Pb_0.98Na_0.02S–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.