Tuning of the Thermoelectric Figure of Merit of CH3NH3MI3 (M=Pb,Sn) Photovoltaic Perovskites

The hybrid halide perovskites, the very performant compounds in photovoltaic applications, possess large Seebeck coefficient and low thermal conductivity, making them potentially interesting high figure of merit (ZT) materials. For this purpose, one needs to tune the electrical conductivity of these semiconductors to higher values. We have studied the CH3NH3MI3 (M-Pb,Sn) samples in pristine form showing very low ZT values for both materials; however, photoinduced doping (in M-Pb) and chemical doping (in M-Sn) indicate that, by further doping optimization, ZT can be enhanced toward unity and reach the performance level of the presently most efficient thermoelectric materials.