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 x 10-2 and an external quantum efficiency of 6.9%, demonstrating their potential for practical application in chiro-optoelectronics.