Exploring and optimizing the performance of inorganic Cs2TiBr6 halide perovskite solar cell with Cu2ZnSnS4 as hole transport layer by device simulation

To seek appropriate substitutes for lead-based perovskite, a perovskite solar cell (PSC) model using Cu2ZnSnS4 as the hole transport layer (HTL) and Cs2TiBr6 as the absorber layer is proposed in this study. The focus of this study is to discuss the drift and diffusion ability of charge carriers in the n-i-p structure formed by ZnO/Cs2TiBr6/Cu2ZnSnS4 under the action of the built-in electric field and concentration gradient. And based on the data simulated by SCAPS-1D, the effects of bandgap structure and device structure on carrier mobility, carrier lifetime, carrier diffusion length, improvement of device performance of the device were further explored. In addition, the effects of HTL types, thickness of HTL, absorber, and ETL, and defect density of absorber on device structure and behavior were analyzed through simulation by SCAPS-1D. The theoretical calculation results obtained by optimizing the structural parameters include 29.24% power conversion efficiency (PCE), 1.22 V open circuit voltage (V-oc ), 26.79 mA cm(-2 )short circuit current (J sc ) and 89.78% fill factor (FF). The conclusion that the n-i-p structure formed by ZnO/Cs2TiBr6/Cu2ZnSnS4 is conducive to carrier migration is vindicated in this study, which enables devices to possess better performance. This study provides a theoretical basis for the application of Cu2ZnSnS4 in inorganic halide-based PSCs.