Synergistic light management and interface engineering of SnO2 for scalable, high-performance air-processed perovskite solar cells

We present a dual-function electron transport layer based on nanostructured tin oxide, engineered through histidine hydrochloride hydrate-induced colloidal self-assembly. The resulting periodic nanoconvex morphology enhances broadband light harvesting through Mie scattering and resonant coupling between adjacent features, reducing average reflectance from 11.52% to 9.39% as verified by finite difference time domain simulations. Concurrently, amino and carboxyl functional groups from histidine coordinate with undercoordinated ions at the SnO2/perovskite interface, effectively reducing trap density and improving energy band alignment. These combined optical and interfacial improvements enable perovskite solar cells fabricated under ambient air conditions to achieve a certified maximum power point tracking power conversion efficiency of 25.89%, representing the highest reported value for ambient-processed n-i-p PSCs. The devices exhibit excellent operational durability, retaining 87% of their initial efficiency after 1200 hours of continuous maximum power point tracking under AM 1.5G illumination. Large-area cells (1 cm2) and modules (17.1 cm2) deliver power conversion efficiencies of 24.79% and 21.09%, respectively. This work offers a scalable and generalizable strategy that integrates photonic structuring with molecular-level defect passivation for advancing high-efficiency perovskite photovoltaics.