Unlocking the potential of 2D material-based charge transport layers for flexible lead-free CsSnBr3 perovskite solar cells

In light of growing environmental concerns, the issues of toxicity and stability have impeded the progress of lead-based perovskite solar cells (PSCs), prompting the development of lead-free alternatives such as cesium tin bromide (CsSnBr3) perovskites. This study provides a comprehensive evaluation of lead-free CsSnBr3 integrated with a two-dimensional (2D) material charge-transporting layer, utilizing density functional theory (DFT) and one-dimensional solar cell capacitance simulator (SCAPS-1D). We systematically optimized various parameters to enhance the PSC performance, including the thickness of CsSnBr3, defect density, interface defects, resistances, and operating temperature. These optimizations resulted in a notable simulated power conversion efficiency (PCE) of 25.11 %, accompanied by a short-circuit current density (JSC) of 33.90 mA cm−2, an open-circuit voltage (VOC) of 0.894 V, and a fill factor (FF) of 82.82 %. The proposed device with refined parameters not only supports ongoing experimental efforts but also presents an innovative approach to structural optimization for all-inorganic flexible lead-free PSC devices, paving the way for future research in this field.