Fabrication and characterization of Cs2SnI6 perovskite films using SnI2 and I2 powders as reactants

In the recent years, cesium tin iodide (Cs2SnI6) double perovskite has emerged as a research hotspot in photovoltaics due to its exceptional stability and outstanding optoelectronic properties. In this work, we have utilized a reactant combination of SnI2 and I2 to prepare uniform Cs2SnI6 films via modified two-step process. The impact of the reaction conditions on the structural, morphological and optical properties is explored. It is found that optimizing the reaction conditions improves the phase stability and morphology of the films. The iodine-rich fabrication of the films ensued in enhanced PL and optical characteristics of the Cs2SnI6 with an optimal bandgap in the range of 1.21–1.34 eV. Additionally, we fabricated and simulated photovoltaic devices (FTO/TiO2/Cs2SnI6/SnO/Au) utilizing the optimized Cs2SnI6 films.