Suppressing Ion Migration through Dual Interface Engineering toward Efficient and Stable Perovskite Solar Modules

Ion migration poses a significant challenge to the stability of perovskite solar cells and also causes a large stability disparity between small devices and large-area modules (PSMs). Here, we developed a dual interface engineering strategy to suppress ion migration in PSMs. Incorporation of Nd 2 O 3 on SnO 2 reduces lattice mismatch, reducing residual strain and suppressing ion migration in perovskite films. Meanwhile, a VO x diffusion barrier layer was employed to mitigate ion diffusion across the electrode interface and prevent electrode corrosion. This combined strategy achieved a high power conversion efficiency (PCE) of 26.22% for small-area PSCs (0.045 cm 2 ) and 89% PCE retention under continuous illumination for 2000 h. Notably, PSM achieved a state-of-the-art efficiency of 22.10%, retaining over 90% of its initial efficiency under continuous illumination for 1600 h. Our work offers an effective strategy to enhance the stability of PSMs and provides deeper insights into the influences of the interface on the ion migration.