Sorrawit Meeklinhom, Madsakorn Towannang, Jirasak Gamonchuang, Kitiphat Sinthiptharakoon, Komsun Lapawae, Nuttaya Sukgorn, Nopporn Rujisamphan, Chalida Imhan, Chalita Ratanatawanate, Pipat Ruankham, Duangmanee Wongratanaphisan, Pongsakorn Kanjanaboos, Anusit Kaewprajak, Pisist Kumnorkaew
Defect formation in perovskite films, particularly due to uncontrolled lead iodide residues, remains a critical challenge in perovskite solar cells (PSCs), leading to nonradiative recombination, voltage losses, and rapid device degradation. Surface passivation is therefore essential to suppress recombination and enhance device stability. In this work, we introduce a simple surface modification strategy using Cu2O-MIL-53-(Al) (CuM) nanoparticles, deposited by spin coating onto perovskite films. The incorporation of CuM effectively regulates residual PbI2, promotes the reduction of the relative PbI2-related diffraction contribution, and modifies the interfacial chemical environment. As a result, the optimized device achieved a power conversion efficiency (PCE) of 20.25% with an open-circuit voltage (V oc) of 1.11 V and negligible hysteresis. Photophysical and electrochemical analyses further indicate reduced nonradiative recombination and improved interfacial carrier dynamics after CuM treatment. In addition, unencapsulated devices retained 96.56% of their initial efficiency after 1000 h under ambient humidity, and the CuM-treated device also exhibited improved thermal-storage stability at 65 °C under N2. These results identify CuM surface treatment as an effective interfacial-engineering approach for improving the performance and storage stability of PSCs.