Directed Chiral Self-Assembly of Purely Organic Phosphors for Room-Temperature Circularly Polarized Phosphorescence

Circularly polarized phosphorescence (CPP) is increasingly recognized in materials science for its unique applications in optoelectronic devices, chiral recognition, and bioimaging. This study underscores a novel directed chiral self-assembly strategy of purely organic phosphors into supramolecular nanostructures to achieve bright room-temperature circularly polarized phosphorescence (RT-CPP). RT-CPP molecules are built on an aromatic carbonyl structure having also Br to mix (n,pi*) and (pi,pi*) characters and to enable the heavy atom effect. Side chains are rationally designed to have strong hydrogen bonding, van der Waals interactions, and a chiral center for directed chiral self-assembly into supramolecular nanostructures. The tightly packed resulting supramolecular nanostructures also impower efficient suppression of molecular motions, thereby minimizing non-radiative decay and facilitating bright CPP emission at room temperature. The developed self-assembled supramolecular structures exhibit RT-CPP with the dissymmetry factor (glum) of approximate to 10-3, a high phosphorescence quantum yield of 4.1%, and a rapid triplet decay time of 180 microseconds. The presented molecular design principle enabling RT-CPP from purely organic phosphors may pave the way for novel photonic materials. This study highlights the creation of supramolecular structures with circularly polarized luminescence (CPL) in fluorescence or phosphorescence at room temperature (glum approximate to 10-3). Through the rational design of organic phosphors having aromatic carbonyl for the El-Sayed rule, bromine for the heavy atom effect, and chiral side chains, the self-assembly is successfully directed into a supramolecular helical structure, exhibiting CPL emission. image