Circularly Polarized Luminescence from Chiral Photonic Crystals of Caesium Lead Halide Perovskites

Abstract The generation and detection of circularly polarized light (CPL) are of importance in many modern technologies such as digital communications, machine vision, bio‐imaging, and 3D displays. In this study, inspired by the fact that various species of plants and animals can efficiently produce and/or perceive CPL with chiral photonic crystal structures, efforts are made to fabricate luminescent chiral photonic crystals with caesium lead halide perovskites, a class of solution‐processable semiconductors that have excellent luminescence properties and readily tunable electronic band gaps. Coupling between the emission frequency of the perovskite and the cavity resonance frequency of the photonic crystal structure can be established at any desired point in the visible region, giving rise to CPL output with a dissymmetry factor up to −0.34. These results suggest a new approach to chiral light‐emitting materials and may contribute to the development of semiconductors with ordered microstructures.