The Multifunctional Antireflection Layer of a Bifacial Perovskite ((FA_0.95Cs_0.05)PbI₃)_0.975(MAPbBr₃)_0.025) Solar Cell Enhances Its Bifaciality, Stability, and Environmental Adaptability

Bifacial perovskite solar cells (PSCs) can significantly enhance power generation by utilizing both front- and rear-side light, yet rear-side efficiency is often limited by reflection losses and environmental factors. A dual-functional organic–inorganic bilayer antireflective coating (ARC) composed of PMMA and MgF 2 was designed to improve both bifaciality and device stability. Three-dimensional finite-difference time-domain (FDTD) simulations optimized the ARC thickness, achieving a 2.37% increase in the rear-side transmittance. The champion cell demonstrated a front-side efficiency of 24.12%, a rear-side efficiency of 21.37%, and 88% bifaciality. Under simulated sand conditions (20% rear-side reflectance), the equivalent bifacial efficiency reached 28.33%. Additionally, the bilayer ARC effectively blocked moisture and oxygen ingress, enhancing device stability under high-humidity and high-temperature conditions, making these PSCs ideal for environments with varying reflectance.