Paradigm shift in perovskite photovoltaics scalability: Spray-engineered 1D/3D perovskite interfaces unlock efficiency and moisture stability

Formamidinium (FA)-based perovskite solar cells (PSCs) hold significant promise for energy resilience applications, where lightweight, portable, and rapidly deployable systems are essential for disaster relief or military operations. However, their commercial viability is hindered by a critical challenge: phase instability under moisture exposure. To overcome this challenge, a highly moisture-stable 1D perovskite layer has been engineered on top of the 3D perovskite through roll-to-roll compatible processing. In this study, pyrrolidinium iodide (PyI) is applied to the surface of formamidinium lead iodide (FAPbI 3 ) perovskite using a pneumatic spray-coating process. This technique leads to the formation of a 1D PyPbI 3 perovskitoid layer, which enhances the overall performance of the 1D/3D perovskite films, especially in regard to the power conversion efficiency (PCE). Compared to traditional spin-coating, the spray-coated PyI delivers superior benefits, demonstrating the promise of this method for developing low-dimensional passivating layers. The spray-based-1D/3D devices achieved an impressive PCE of 21.64%, marking the highest reported efficiency for FAPbI 3 perovskites modified by PyI using a scalable roll-to-roll spray technology. This work represents the first successful demonstration of pneumatic spray-coated 1D perovskitoid compatible with high-throughput roll-to-roll processing.