Unraveling the Potential Pathways for Improved Performance of EDA_0.01(GA_0.06(FA_0.8Cs_0.2)_0.94)_0.98SnI₂Br‐Based Solar Cells

Abstract

This article comprehensively investigates the photovoltaic performance of a 3% GeI2‐doped ASnI2Br 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/C60/Ag) and utilizes EDA0.01(GA0.06(FA0.8Cs0.2)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 ASnI2Br/C60 interface, doping of the electron‐transport layer (ETL), and its interface with the absorber, and 3) valence band offset at the PEDOT:PSS/ASnI2Br interface, and doping of the hole‐transport layer and its interface with the absorber. Additionally, the impact of series resistance (Rs) 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 C60 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.