Designing a high performance solar cell structure requires the understanding of material innovation, device engineering, charge behavior, operation characteristics and efficient photoconversion of light to generate electricity. This study offers a detailed numerical evaluation of the device physics in a highly efficient methylammonium‐based perovskite solar cell (PSC) of the configuration, FTO/WO3/CH₃NH₃SnI₃/GO/Fe. Utilizing the SCAPS‐1D device simulator, an impressive open‐circuit voltage (Voc) of 1.3184 V, short‐circuit current density (Jsc) of 35.10 mA/cm², Fill factor (FF) of 78.38%, and power conversion efficiency (PCE) of 36.24% were achieved. The model cell exhibits a robust photon capture of 100% quantum efficiency between 360 and 750 nm. The study also presents temperature‐dependent band alignment diagram which posted a built‐in potential (Vbi) of 0.62 eV. The Vbi at 400 K was found to be 0.58 eV indicating that the model cell exhibits a decent temperature tolerance, and can retain approximately 93% of its power at 400 K. Through Mott‐Schottky capacitance analysis, deeper insights into the space‐charge region are inferred, while recombination‐generation investigations emphasize the significance of electronic properties in optimizing device performance. This paper, therefore, lays the foundation for future studies, offering clear pathways for device optimization and identifying key areas that require further investigation.