Recent Progress in Perovskite‐Based Reversible Photon–Electricity Conversion Devices

Abstract Solution‐processed metal halide perovskites have the advantages of a tunable bandgap, excellent charge transport properties, and suitable exciton binding energy. They therefore emerge as promising semiconductors for efficient perovskite solar cells (PSCs) and bright perovskite light‐emitting diodes (PLEDs). In addition, these devices possess a similar planar–heterojunction architecture, thus novel dual‐functional perovskite light‐emitting solar cells (PLESCs) that can realize electrical‐to‐optical and optical‐to‐electrical conversion on one device are developed. To date, high‐performance PLESCs with 17.2% electroluminescence external quantum efficiency and 25.2% power conversion efficiency are achieved using a holistic optimization approach. However, a comprehensive review focusing on dual‐functional PLESCs with discussion on their development and limitations, remains lacking. Herein, the rapid progress in PLESCs, including 0D quantum dot, 2D Ruddlesden–Popper, and 3D bulk perovskite devices, is reviewed. First, the fundamental understanding of the device structure and working principle of PLESCs is overviewed. Second, the state‐of‐the‐art developments for simultaneously achieving high‐efficiency PSCs and PLEDs, focusing on defect passivation, interface optimization, energy level alignment, and dimensional control, are comprehensively summarized. Finally, the authors offer some perspectives for future trends in the development of promising PLESCs, which can provide guidelines for this emerging field.