Regulating Circularly Polarized Luminescence in Zero-Dimensional Chiral Hybrid Metal Halides

Polarization reflects the inherent properties of light. Circularly polarized light, in which the electric field rotates in a circle along the direction of propagation, contains rich optical information and exhibits angle-independent characteristics. This feature makes it widely applicable in asymmetric synthesis, 3D display, and light-emitting devices. Research on circularly polarized luminescence (CPL) has garnered significant attention in recent years. CPL-active materials range from small molecules to supermolecules and from chiral rare-earth complexes to nanosuperstructures. With advancements in developing new materials and technology in chiral science, this field has rapidly developed, and extensive efforts are focused on the development of CPL-active materials with both high photoluminescence quantum yield (PLQY) and large luminescence dissymmetry factor (g_lum). Among these materials, zero-dimensional (0D) chiral hybrid metal halides (CHMHs) characterized by isolated inorganic polyhedra, which combine the chirality of organic cations with excellent photophysical properties of inorganic polyhedra, have emerged as a promising class of CPL-active materials. Despite recent advancements in the design and preparation of CPL-active 0D CHMHs, several challenges remain. Considering the demands of real applications, high PLQY, large g_lum value, and a range of CPL colors are all required.