A Chiral Cocrystal Strategy Producing Room‐Temperature Phosphorescence and Enhancing Circularly Polarized Luminescence

Abstract The maintenance of triplet excitons to produce room‐temperature phosphorescence while simultaneously improving the luminescence dissymmetry factor (g _lum ) and photoluminescence quantum yield (PLQY) makes the preparation of circularly polarized room‐temperature phosphorescence (CP‐RTP) materials challenging. Herein, two chiral cocrystals are reported with CP‐RTP using S/R‐1‐(1‐Naphthyl)ethanol (S/R‐1‐nea) as the donor and 1,2,4,5‐Tetracyanobenzene (TCNB) as the acceptor. Simultaneous enhancement of g _lum and PLQY is accomplished, with the greatest phosphorescence in the PLQY of ≈31% and |g _lum | of 0.065, which is one of the highest |g _lum | in cocrystals. Doping two chiral cocrystals into the polyvinyl alcohol (PVA) matrix resulted in polymer films with circularly polarized long afterglow luminescence, indicating the potential for multilevel encryption applications. This study provides a novel approach to achieve the dual improvement of g _lum and phosphorescence PLQY, and broadens the application prospects of CP‐RTP materials.