Chemical Design of Organic Interface Modifiers for Highly Efficient and Stable Perovskite Solar Cells

Perovskite solar cells (PSCs) have demonstrated rapid progress in their power conversion efficiencies (PCEs)—from 3.8% in 2009 to 25.7% in 2022—and they have received considerable attention as a promising future photovoltaic (PV) technology. However, the operational stability of PSCs is still inadequate to satisfy the standards for commercial applications. Interface engineering has become one of the most important strategies to push PSCs’ efficiency and stability for practical use. Among the various interface engineering approaches, organic interface modifiers (OIMs) have been frequently used by the PSC field to address the issues limiting PSC stability at high efficiency levels. In this perspective, the chemical structures of state‐of‐the‐art OIMs are discussed, and their characteristics are reviewed, as well as the impact on device performance associated with key device interfaces (e.g., metal oxide/perovskite and organic transport layer/perovskite interfaces) from a chemical and materials engineering point of view is discussed. Design considerations and the authors' perspective are discussed, on the basis of representative literature examples, for building new, customized organic OIMs to further improve PSC efficiency and stability toward commercialization. Recent progress on organic interface modifiers (OIMs) is reported according to the following categories: the anchoring groups (metal oxide, perovskite, and organic material) and frameworks (backbone and spacer). Then various strategies and effects of properly designed OIMs are discussed. Finally, an outlook on the application of extended OIM technology for the future development of efficient and stable PSCs is provided.