Photoisomerizing Molecular Modification on the Buried Interface of Perovskite Solar Cells

Abstract The operational stability issues of perovskite devices under illumination pose significant challenges for practical applications, attributed to substantial alterations in lattice distortion, defect enrichment, and stress distribution in the excited state. However, most existing modification strategies predominantly focus on defect elimination and chemical transformations at the ground state level, which may not yield the desired outcomes in the excited state. To address this challenge, this study introduces a dynamic management strategy utilizing 4‐aminoazobenzene hydrochloride, which exhibits photoinduced cis‐trans isomerism, for the buried interface within perovskite devices. Experimental results demonstrate that the isomerized molecules anchored at the buried interface effectively inhibit the formation of photoinduced defects and mitigate interfacial stress accumulation. A comprehensive mechanism of the dynamic management through cis‐trans isomerism transformation has been proposed to elucidate the buried interface modification process. Consequently, the device efficiency and operational stability have been markedly enhanced, achieving a peak efficiency of 25.65% and retaining over 92% of its initial efficiency after 1200 h continuous illumination under International Summit on Organic Photovoltaic Stability protocol (ISOS ).