Structural Distortion‐Driven Chirality Transfer and Circularly Polarized Light Emission in Quasi‐2D Perovskites Based Light‐Emitting Diodes

Abstract Chiral halide perovskites have emerged as promising materials for spin‐optoelectronic devices owing to their ability to emit circularly polarized light (CPL) through spin‐selective processes. However, the realization of high dissymmetry factors in perovskite‐based circularly polarized light‐emitting diodes (CP‐LEDs) remains challenging. Herein, CP‐LEDs based on quasi‐2D perovskites incorporating two types of chiral materials are demonstrated, which achieve high circular polarization. R‐/S‐methylbenzylammonium iodide (MBAI) is employed to construct quasi‐2D perovskite structures and R‐/S‐1,1′‐binaphthyl‐2,2′‐diyl hydrogen phosphate (BHP) to enhance chiral distortion. Enhanced CPL emission with higher dissymmetry factors is observed due to a synergistic effect of the matching handedness of MBAI and BHP. The enhanced circular dichroism in the absorption band of the n = 1 2D perovskite reveals the presence of chiral distortion, which leads to strong CPL emission. The results of density functional theory calculations and micro‐strain analysis are further supported by the observed chiral distortion of the inorganic perovskite lattice. Moreover, BHP effectively passivated the perovskite defects through its phosphate groups. The resulting CP‐LEDs exhibit an enhanced electroluminescence dissymmetry factor of 7.5 × 10 −2 and an external quantum efficiency of 6.9%, demonstrating their potential for practical application in chiro‐optoelectronics.