Optimization and Comparative Analysis of Electron Transport Layers for High‐Performance InGeCl3‐Based Perovskite Solar Cells

Abstract Indium germanium chloride (InGeCl 3 ) emerges as a promising lead‐free absorber material for photovoltaic (PV) applications owing to its direct bandgap (1.29 eV), strong light absorption, and excellent structural and thermodynamic stability. This study employs numerical simulations using SCAPS‐1D to investigate the photovoltaic performance of InGeCl 3 ‐based solar cells, incorporating fluorine‐doped tin oxide (FTO) as the transparent conducting oxide and three distinct electron transport layers (ETLs): CdS, In 2 S 3, and TiO 2 . Comprehensive simulations were conducted to evaluate the effects of absorber and ETL layer thickness, defect density, doping density, temperature, and parasitic resistances on device performance. Among the evaluated architectures, the FTO/CdS/InGeCl 3 /Au configuration achieved the highest power conversion efficiency (PCE) of 28.74%, with an open‐circuit voltage (V OC ) of 0.935 V, short‐circuit current density (J SC ) of 35.13 mAcm −2 , and a fill factor (FF) of 87.52%. In comparison, the TiO 2 and In 2 S 3 ETL‐based configurations attained PCEs of 24.61% and 23.26%, respectively. The thermal stability analysis and parasitic resistance effects reveal that CdS‐based devices exhibit superior performance across operational conditions, while TiO 2 ‐based structures show higher thermal stability. These results offer critical insight into the design and optimization of InGeCl 3 ‐based perovskite solar cells, paving the way for efficient and stable lead‐free photovoltaic technology.