Hydroxyl Interfacial Engineering for Self-Assemble Monolayers Anchoring on NiO_x Enables Efficient and Stable...

The performance of inverted perovskite solar cells (PSCs) is critically constrained by interfacial losses arising from the insufficient coverage and weak adhesion of self-assembled monolayers (SAM). Herein, we report a SAM regulation strategy by mixing hydroxylated V₂CT_x MXene (V₂C-OH) with nickel oxide (NiO_x), which can provide abundant hydroxyl sites for SAM anchoring, thereby forming a uniform and dense SAM layer. First-principles calculations further reveal that the binding energy between SAM and hydroxyl groups on V₂C-OH is stronger than that on pristine NiO_x, explaining the enhanced thermal stability of SAM on the hybrid substrate. Meanwhile, the highly ordered and tightly packed SAM layer promotes vertical growth and [001]-preferred orientation of perovskite grains. Therefore, the introduction of V₂C-OH enables a top-down modulation of the NiO_x, SAM, and perovskite layers, improving their morphology and interfacial properties. The resulting PSCs achieve a champion power conversion efficiency of 26.6% (certified at 26.2%) for a 0.0524 cm² device and 24.7% for a 1 cm² device, along with outstanding long-term operational stability.