Numerical Optimization of All‐Inorganic CsPbI₂Br Perovskite Solar Cells

Perovskite solar cells (PSCs) have substantially increased their power conversion efficiency (PCE) to more than 25% in recent years. However, the instability of these devices is still a strong obstacle for their commercial applications. Recently, CsPbI 2 Br‐based all‐inorganic PSCs have shown greater long‐term stability and commercialization potential. Currently, the 1.92 eV CsPbI 2 Br top cell, combined with a 1.31 eV CsPb 0.4 Sn 0.6 I 3 : GLE device, enables two‐terminal interconnected perovskite tandem solar cells (2T‐IPTSCs) to reach a champion efficiency of 22.57% (certified at 21.92%). In this study, we adopted the top‐cell configuration of a tandem PSC, ITO/ZnO/CsPbI 2 Br/NiO x /Au. We employed the SCAPS‐1D software (ver. 3.3.12) to simulate and compare the photovoltaic performance of devices using various inorganic materials as the hole transport layer (HTL) and electron transport layer (ETL). Simulation results revealed that MoO 3 and IGZO are the most suitable choices for HTL and ETL, respectively. Based on this optimized structure, further improvements were achieved by tuning the absorber layer thickness, doping concentration, defect density ( N t ), and back contact metal. Under optimal conditions, the all‐inorganic CsPbI 2 Br‐based PSC achieved a maximum PCE of 21.41%. These results indicate that there remains considerable potential for further enhancing the performance of such devices.