Two‐Dimensional Metal‐Halide Perovskite‐based Optoelectronics: Synthesis, Structure, Properties and Applications

In the past decade, metal‐halide perovskites have attracted increasing attention in optoelectronics, due to their superior optoelectronic properties. However, inherent instabilities of conventional three‐dimensional (3D) perovskites over moisture, heat, and light remain a severe challenge before the realization of commercial application of metal‐halide perovskites. Interestingly, when the dimensions of metal‐halide perovskites are reduced to two dimensions (2D), many of the novel properties will arise, such as enlarged bandgap, high photoluminescence quantum yield, and large exciton binding energy. As a result, 2D metal‐halide perovskite‐based optoelectronic devices display excellent performance, particularly as ambient stable solar cells with excellent power conversion efficiency (PCE), high‐performance light‐emitting diodes (LEDs) with sharp emission peak, and high‐sensitive photodetectors. In this review, we first introduce the synthesis, structure, and physical properties of 2D perovskites. Then, the 2D perovskite‐based solar cells, LEDs, and photodetectors are discussed. Finally, a brief overview of the opportunities and challenges for 2D perovskite optoelectronics is presented.