Ruddlesden–Popper Perovskites: Synthesis and Optical Properties for Optoelectronic Applications

Ruddlesden–Popper perovskites with a formula of (A′)(2)(A)(n) (−1)B(n)X(3) (n) (+1) have recently gained widespread interest as candidates for the next generation of optoelectronic devices. The variations of organic cation, metal halide, and the number of layers in the structure lead to the change of crystal structures and properties for different optoelectronic applications. Herein, the different synthetic methods for 2D perovskite crystals and thin films are summarized and compared. The optoelectronic properties and the charge transfer process in the devices are also delved, in particular, for light‐emitting diodes and solar cells.