Repairing humidity-induced interfacial degradation in quasi-2D perovskite solar cells printed in ambient air†

Due to the moisture sensitivity of organic cations, the presence of adsorbed water (H₂O_ad) during the printing process in air tends to complicate the structure transformation and poses potential hazards to the long-term operational stability, particularly in alternating-cation interlayer layered halide perovskite (LHP) solar cells with a sophisticated organic cation composition. Here, H₂O_ad as a nucleation medium skillfully expanded the humidity processing window for scalable LHP solar cells, revealing the feasibility of the thermodynamically favored reaction pathways in promoting atomic layer deposition in direct contact with the perovskite films without damage. Moreover, the interfacial aging mechanism and inhibition of ion diffusion were comprehensively investigated. Finally, target devices based on GA(MA)₅Pb₅I₁₆ (n = 5) with effective areas of 0.09 cm² and 1.01 cm² exhibited impressive power conversion efficiencies of 21.0% and 19.7%, respectively, which are some of the highest values in the large-area 2D LHP devices. The target device maintained 93% of its initial efficiency over 170 days (4080 h) in an air environment, while further validating the scalability of our strategy on LHP modules with an area of 100 cm².