Enhanced thermoelectric performance in inorganic CsSnI3 perovskite by doping with PbI2

Abstract The inorganic halide perovskite CsSnI3 has attracted significant attention for use as a thermoelectric material owing to its ultralow thermal conductivity and unique electrical properties. In this study, we report lead iodide (PbI2) doping to optimize the thermoelectric performance of bulk CsSnI3. The addition of a small amount of PbI2 narrowed the bandgap of CsSnI3 and modulated its carrier concentration, improving the electrical conductivity of CsSnI3. Moreover, the lattice distortion caused by PbI2 doping led to a significant decrease in the lattice thermal conductivity of CsSnI3. Finally, the thermoelectric performance was enhanced, and the highest ZT value attained was 0.14 at 523 K.