Single Step and Solution Process Fabrication of Mesoporous ZnOS Thin Film as an Effective Electron Transport Layer for the Cs‐Based Halide Double PSCs

In this study, the ZnOS thin films have been fabricated by the spin coating technique for applying as an effective electron transport layer (ETL) for halide double perovskite solar cells (PSCs). The impact of the number of coatings and/or thickness variations on ZnOS thin films' properties has been analyzed in terms of surface morphology, crystal structure, elemental, and optoelectronic characteristics, and has been found to have a substantial impact on the properties of prepared thin films. For better understanding, an undoped ZnO thin film has also been analyzed alongside the ZnOS thin films. Also, the performance variation of halide double PSCs has been investigated utilizing ZnOS as an effective ETL by means of a solar cell capacitance simulator one‐dimensional software. The highest power conversion efficiency (PCE) with the configuration of FTO/ZnOS/Cs 2 AgBi 0.75 Sb 0.25 Br 6 /Cu x O/Au of 16.21% was obtained for single‐coated ZnOS thin films. The result implies that ZnOS can more efficiently extract the charge carriers from the absorber layer of PSCs than pure ZnO. We anticipate that the findings of this study will lead to fresh insights into the practical applications of ZnOS as the optimum ETL for halide double PSCs.