Design and Simulation of All‐Inorganic Wide‐Bandgap CsPbIBr ₂ Solar Cells for Indoor Photovoltaic Applications

Abstract

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 CsPbIBr 2 perovskite material as a promising photoactive absorber for perovskite solar cells (PSCs) designed for indoor applications. CsPbIBr 2 exhibits a favorable balance between optical bandgap and phase stability among other all‐inorganic constituents. Additionally, CsPbIBr 2 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 CsPbIBr 2 ‐based solar cell demonstrating a power conversion efficiency (PCE) of 11.01% under 1‐sun illumination, with an initial device structure of ITO/ZnO/CsPbIBr 2 /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 CsPbIBr 2 PSCs as a promising candidate for indoor PV applications.