Introducing a New and Highly Efficient Double‐Absorber Solar Cell with Combination of Sr₃PBr₃ and CsPbI₃ Perovskites

This study presents an innovative strategy to enhance perovskite solar cell (PSC) performance by employing a dual absorber layer configuration using Sr 3 PBr 3 (A 3 BX 3 ) and CsPbI 3 (ABX 3 ). Utilizing the SCAPS‐1D simulation tool, the photovoltaic (PV) properties of these materials are thoroughly analyzed, focusing on bandgap alignment, layer thickness, defect density, and other key parameters affecting overall device efficiency. The simulation reveals that single‐junction PSCs using Sr 3 PBr 3 and CsPbI 3 achieved efficiencies of 20.84% and 19.65%, respectively. However, integrating CsPbI 3 with lead‐free Sr 3 PBr 3 in a double structure significantly improved performance. The optimized device architecture FTO/ZnS/CsPbI 3 /Sr 3 PBr 3 /Au with a total absorber thickness of 1.2 μm and a defect density of 1 × 10 1 0 cm − 3 for both layers, reached power conversion efficiency of 23.86%, short‐circuit current density of 25.01 mA cm −2 , and open‐circuit voltage of 1.06 V. The fill factor is notably high at 88.38%. These findings confirm that the dual absorber strategy significantly enhances light absorption and charge carrier dynamics, thereby boosting PSC efficiency. The study positions Sr 3 PBr 3 as a promising, lead‐free alternative that complements CsPbI 3 , paving the way for the development of high‐efficiency, stable, and environmentally friendly photovoltaic technologies.