Engineering of Double Absorber Organic‐Perovskite Solar Cells for >34% Efficiency with V ₂ O ₅ as Back Surface Field Layer

To overcome the Shockley–Queisser limit in single‐junction perovskite solar cells (PSCs), this study explores a high‐efficiency organic double perovskite active layer (DPAL) design using methylammonium lead iodide (MAPbI 3 ) and methylammonium tin iodide (MASnI 3 ) as complementary absorbers. Four device configurations are analyzed via SCAPS‐1D simulation: two single‐junction cells (FTO/WS 2 /MAPbI 3 /Au and FTO/WS 2 /MASnI 3 /Au) and two DPAL cells (FTO/WS 2 /MAPbI 3 /MASnI 3 /Au and FTO/WS 2 /MAPbI 3 /MASnI 3 /V 2 O 5 /Au). The DPAL design with a V 2 O 5 back surface field achieves a peak power conversion efficiency of 34.14%, with a short‐circuit current density ( J SC ) of 33.98 mA cm 2 , open‐circuit voltage ( V OC ) of 1.13 V, and fill factor (FF) of 88.55%. By varying parameters such as layer thickness, doping, defect density, and interface quality, key optimization strategies are identified. The dual‐absorber design enhances spectral coverage and reduces recombination, offering a compelling path for scalable, high‐efficiency perovskite photovoltaics.