Computational modeling of Cs₃Sb₂I₉-based novel architecture under WLED illumination for indoor photovoltaic applications

This manuscript presents a comprehensive evaluation of Cs₃Sb₂I₉ (E_g = 1.95 eV) as a potential absorber for indoor photovoltaic (IPV) applications. Using computational modeling, we developed a baseline model of the device structure (FTO/TiO₂/Cs₃Sb₂I₉/PolyTPD(poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine)/Au), which experimentally achieved a power conversion efficiency (PCE) of 3.7% under white light-emitting diode (WLED) illumination at 3.2 W m⁻² (1000 lx). By increasing the source transmission power density from 3.2 W m⁻² (6%) to 53.31 W m⁻² (100%), we significantly enhanced the device’s performance. Key parameters such as absorber layer thickness and defect density, along with parameters of the electron transport layer (ETL) and hole transport layer (HTL), were optimized, such as doping concentration, electron affinity (χ), and bandgap (E_g), were optimized. Our simulations demonstrated that the optimized device can achieve a remarkable PCE of 38.77%, with an open-circuit voltage (V_OC) of 1.47 V, a short-circuit current density (J_SC) of 1.55 mA cm⁻², and an excellent fill factor (FF) of 89.09%. Additionally, we proposed a new device architecture, AZO/TNT/Cs₃Sb₂I₉/SrCu₂O₂/Ni, capable of delivering 38.77% PCE under WLED illumination. This study highlights the critical role of computational modeling in optimizing device design, offering a cost-effective and efficient alternative to experimental methods.