Design and Simulation of All-Inorganic Wide-Bandgap CsPbIBr2 Solar Cells for Indoor Photovoltaic Applications

The raising demand for efficient and stable energy sources for indoor applications demands the development of high-performance photovoltaic (PV) materials. This study examines the potential of the all-inorganic CsPbIBr2 perovskite material as a promising photoactive absorber for perovskite solar cells (PSCs) designed for indoor applications. CsPbIBr2 exhibits a favorable balance between optical bandgap and phase stability among other all-inorganic constituents. Additionally, CsPbIBr2 possesses a wide direct bandgap of 2.05 eV, elevated absorption coefficient, and high carrier mobilities, compelling it well-suited for harnessing photon energy from indoor lighting sources. Our research commenced with an experimental CsPbIBr2-based solar cell demonstrating a power conversion efficiency (PCE) of 11.01% under 1-sun illumination, with an initial device structure of ITO/ZnO/CsPbIBr2/Spiro-OMeTAD/Au. We initiated our investigation using SCAPS-1D to validate the simulation approach, replicating experimental current–voltage characteristics and identifying a critical limitation in the single electron transport layer (ETL) design: suboptimal band alignment. This insight drives a comprehensive optimization strategy relating a double ETL configuration, exploring optimal transport layer materials, followed by analyzing absorber layer thickness and defect concentrations. Through this methodical approach, we progressively enhanced the cell’s performance, achieving a remarkable 21.85% a PCE under 200 lux, and a 2900 K indoor LED illumination. The simulation results provided in this study reveal the prospective of CsPbIBr2 PSCs as a promising candidate for indoor PV applications.