Reinforced Anchor for Scalable Self-Assembled Monolayer to Attain High-Performance Perovskite Solar Modules

The synergistic integration of nickel oxide (NiO_x) with self-assembled monolayers (SAMs) as hole transport layers boosts perovskite solar cells (PSCs) performance, where downward phosphate anchoring (DPA) enhances hole extraction efficiency but poses scalability challenges, with SAMs configuration-performance correlations remaining unclear. Herein, a Brønsted acid pretreatment combined with nitrate anions occupying active sites on NiO_x is employed to suppress conventional downward phosphate anchoring and establish an upward phosphate anchoring (UPA) configuration, whereby SAMs anchor not only onto the perovskite layer but also the NiO_x surface, effectively bridging hole-transport in between the interface. This UPA configuration exhibits enhanced interfacial adhesion and improved energy band alignment, while also increasing the surface energy, which promotes perovskite crystallization and facilitates stress release. As a result, the champion PSC achieves an impressive power conversion efficiency of 25.9% with excellent stability. Furthermore, this configuration enhances the suitability of SAMs for large-area perovskite modules, enabling a 156 × 156 mm² module to reach a high efficiency of 22.05%. This work promotes the application of SAMs in the commercialization of perovskite photovoltaics and stimulates further investigation into the relationship between SAM anchoring configurations and interfacial properties.