Phase Regulation of Layered Perovskites toward High-Performance Light-Emitting Diodes

As a promising family of semiconductor materials for high-quality displays, quasi-2D perovskites have gained a significant amount of attention in the field of light-emitting diodes for their superior optoelectronic properties compared with their 3D counterparts. The intrinsic multiple-quantum-well characteristics induced by reducing the crystal dimensionality enable perovskite emitters to possess high photoluminescence quantum yield and good film morphology. It is demonstrated that the n-value distribution of quasi-2D perovskites, where n refers to the number of inorganic MX₆ octahedron layers, has a strong impact on the electroluminescence efficiency and stability of perovskite light-emitting diodes (PeLEDs). In this review, the crystal structure of quasi-2D perovskites, the formation origin of different n-value distributions, and their optoelectronic characteristics are first introduced. Then, the mainstream strategies for regulating the phase distribution of layered perovskites are systematically reviewed to suggest their great significance in boosting the performances of PeLEDs. Lastly, the current deficiencies and potentially valuable research directions of phase distribution management for efficient and stable quasi-2D PeLEDs are provided.