Effect of Precursor Solution Aging on the Thermoelectric Performance of CsSnI 3 Thin Film

Inorganic CsSnI3 based perovskite crystals are interesting thermoelectric materials, owing to their unusual electronic properties. Here we report the thermoelectric power performance of a solution-coated CsSnI3 thin film from the viewpoint of carrier concentration optimizations. It was found that the carrier concentration can be changed by altering the aging time of the precursor solution. X-ray photoelectron spectroscopy analysis showed that the concentration of metallic Sn4+ increased as the solution aging time increased. This made possible to explore the relationship between carrier concentration and thermoelectric power factor. After controlling Sn4+ concentrations, we report a power factor of 145.10 μW m−1 K−2 , along with electrical conductivity 106 S/cm and Seebeck coefficient of 117 μV/K, measured at room temperature.