SCAPS-1D Simulation of Various Hole Transport Layers’ Impact on CsPbI2Br Perovskite Solar Cells Under Indoor Low-Light Conditions

This study presents the first comprehensive theoretical investigation utilizing SCAPS-1D simulation to systematically evaluate eight hole transport materials for CsPbI2Br perovskite solar cells under authentic indoor LED conditions (560 lux, 5700 K color temperature). Unlike previous studies employing simplified illumination assumptions, our work establishes fundamental design principles for indoor photovoltaics through rigorous material property correlations. The investigation explores the influence of layer thickness and defect concentration on performance to identify optimal parameters. Through detailed energy band alignment analysis, we demonstrate that CuI achieves superior performance (PCE: 23.66%) over materials with significantly higher mobility, revealing that optimal band alignment supersedes carrier mobility under low-light conditions. Analysis of HTL and absorber layer thickness, bulk defect concentration, interface defect density, and an HTL-free scenario showed that interface defect concentration and absorber layer parameters have greater influence than HTL thickness. Remarkably, ultra-thin HTL layers (0.04 μm) maintain >99% efficiency, offering substantial cost reduction potential for large-scale manufacturing. Under optimized conditions of a 0.87 μm absorber layer thickness, defect concentration of 1015 cm−3, interface defect concentration of 109 cm−3, and CuI doping concentration of 1017 cm−3, PCE reached 28.57%, while the HTL-free structure achieved 17.6%. This study establishes new theoretical foundations for indoor photovoltaics, demonstrating that material selection criteria differ fundamentally from outdoor applications.