Rational Engineering of Phase‐Pure 2D Perovskite Solar Cells

Abstract 2D perovskite structures have gained significant attention due to their reliable long‐term stability. Unlike quasi‐2D perovskites, phase‐pure 2D perovskites exhibit a flattened energy landscape and low energy transfer losses, offering substantial benefits for enhancing device efficiency and stability. Recent research on phase‐pure 2D perovskites has shown significant progress, attributed to their unique properties. This review delineates advancements in the study of phase‐pure 2D perovskite materials and elucidates the relationships between crystal structure design, growth, and device performance regulation. Additionally, it summarizes techniques for characterizing phase‐pure 2D structures and methods for their precise synthesis. Finally, an outlook on the future development of phase‐pure 2D perovskites, highlighting the scientific and technological challenges in current research is provided.