In this study, we introduce a coupled experimental-computational framework to evaluate indium-doped cerium dioxide (CeO \(_2\) ) as an engineered electron transport layer (ETL) for a novel tin-based perovskite solar cells (PSC). While pristine CeO \(_2\) is widely employed as an ETL, its limited electrical conductivity and suboptimal charge transport properties restrict efficient electron extraction, making dopant-driven modification a critical yet insufficiently quantified strategy. In-doped CeO \(_2\) thin films with doping concentration of 0%, 2%, 4%, 6% and 8% are deposited via spray pyrolysis technique. The prepared films are systematically characterized using UV–vis-NIR spectroscopy and Hall-effect measurements to extract their optical and electrical properties. These analysis demonstrates a remarkable enhancement in carrier concentration and mobility, accompanied by a marked increase in electrical conductivity compared with undoped CeO \(_2\) , reflecting improved charge transport characteristics within the ETL. The experimentally derived parameters are then incorporated into a 3D optoelectronic model, developed by finite element method (FEM), of the complete device. Significant new results show that doping improves photovoltaic performance. According to the findings, photogeneration ( \(G_{tot}\) ) increases to 3.30 \(\times \) \(10^{28}\) \(m^{-3} s^{-1}\) , short-circuit current density ( \(J_{sc}\) ) to 35.1 \(mA/cm^{2}\) , and power-conversion efficiency (PCE) to 32.3% at the doping concentration of 6%. Besides, owing to the important impact of metal electrodes on the device efficiency, we investigated several electrode materials. These results serve as a valuable guide for PSC design and efficiency forecasting before the actual experiment verification.
