Interface engineering using Y2O3 scaffold to enhance the thermoelectric performance of CsSnI3 thin film

Abstract Solution processed Cesium Tin halide perovskite (CsSnI3) are inorganic crystal to be explored for thermoelectric applications. Here, we report a novel strategy using an inorganic Y2O3 scaffold to improve the thermoelectric performance. The additional Y2O3 influence the CsSnI3 crystal growth and favor more conducting behavior with intrinsic defects (Sn4+) formation. Therefore, the resulting solution processed composite film Y2O3/CsSnI3 show much improved electrical conductivity of ∼310 S/cm as compared to ∼98 S/cm of pristine CsSnI3 film. Under the influence of Y2O3, the resulting phonon scattering path was enhanced significantly due to formed defects/vacancy and reduced CsSnI3 crystal size, which showed a reduction in thermal conductivity from 0.74 W/mK to 0.28 W/mK. This work paves a new paradigm to improve the thermoelectric performance of solution based thermoelectric generator.