Unraveling the Potential Pathways for Improved Performance of EDA0.01(GA0.06(FA0.8Cs0.2)0.94)0.98SnI2Br‐Based Solar Cells

This article comprehensively investigates the photovoltaic performance of a 3% GeI 2 ‐doped ASnI 2 Br absorber in a solar cell. The cell features an inverted structure (fluorine‐doped tin oxide [FTO]/poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate [PEDOT:PSS]/absorber/C 60 /Ag) and utilizes EDA 0.01 (GA 0.06 (FA 0.8 Cs 0.2 ) 0.94 ) 0.98 as the A‐site cation (EDA for ethylenediamine; GA for guanidinium; FA for formamidinium). Through systematic numerical simulation and optimization, the photovoltaic performance of the solar cell is enhanced by sequentially optimizing several parameters: 1) absorber thickness and defect density, 2) conduction band offset at the ASnI 2 Br/C 60 interface, doping of the electron‐transport layer (ETL), and its interface with the absorber, and 3) valence band offset at the PEDOT:PSS/ASnI 2 Br interface, and doping of the hole‐transport layer and its interface with the absorber. Additionally, the impact of series resistance ( R s ) variation on device performance is investigated. Starting with an initial power conversion efficiency (PCE) of 4.86%, the systematic numerical optimization process elevates it to an impressive 18.55%. Furthermore, a final cell structure is proposed where C 60 is replaced with indium‐doped tin oxide (ITO) as the ETL layer. This optimized FTO/PEDOT:PSS/absorber/ITO structure demonstrates a remarkable PCE of 18.68%. These findings hold significant promise for advancing tin‐perovskite solar cell technology.