Simulation‐Based Analysis of Environmentally Friendly Perovskite Solar Cells: Projecting 21.61% Efficiency with Lead‐Free CsSn_0.5Ge_0.5I₃

In this study, a simulation‐based analysis of environmentally friendly, lead‐free perovskite (PVK) solar cells (PSC) with high power conversion efficiency (PCE), is presented. Various PVK materials, including lead‐, tin‐, germanium‐, and tin–germanium‐based compounds, are evaluated through simulations to explore their impact on device performance. Among these, CsSn 0.5 Ge 0.5 I 3 demonstrates the highest simulated efficiency, with a rectangular cell architecture of 0.45 × 0.9 mm. Key parameters such as thickness, temperature, doping concentration, and bandgap are systematically varied in the simulations to study their effects on device performance. The optimized architecture is found to be Au/Spiro‐MeOTAD (hole‐transport layer)/CsSn 0.5 Ge 0.5 I 3 /TiO 2 (electron‐transport layer)/FTO, achieving a simulated PCE of 21.61%, with an open‐circuit voltage ( V oc ) of 1.2 V, short‐circuit current density ( J sc ) of 21.32 mA cm − 2 , and fill factor of 84.43%. Furthermore, in this study, detailed electrical simulations (electric field distribution, Shockley–Read–Hall recombination, and electron and hole concentrations) and thermal simulations (nonradiative recombination heating, joule heating) of the device are included. In this work, the potential of lead‐free PSCs is underscored and the importance of continuous simulation studies to design eco‐friendly, high‐efficiency photovoltaic devices is highlighted.