High‐Performance Circularly Polarized Phosphorescence by Confining Isolated Chromophores with Chiral Counterions

Abstract Organic room‐temperature phosphorescence (RTP) featuring circularly polarized luminescence (CPL) is highly valuable in chiroptoelectronics, but the trade‐off issue between luminescence efficiency ( Φ ) and dissymmetry factor ( g lum ) is still challenging to be solved. Here, chiroptical ionic crystals ( R/S ‐DNP) are constructed through ionization‐induced assembly, in which isolated chromophore of carboxylic anion is tightly confined by the surrounding chiral counterions. The long‐range ordered and chiral counterions with asymmetric stacking are closely connected with isolated chromophores for molecular assembly via high‐density electrostatic interactions, thus enabling the simultaneous realization of excellent single‐molecule RTP emission and efficient chirality transfer. The synchronous enhancement of Φ P and g lum is further achieved as 43.2% and 0.13, respectively. In view of the excellent CPL performances, the ionic materials hold the promising chiroptical encryption via programmable control in an electric‐driven circularly polarized phosphorescent device. This result not only makes deeper insights into the relationship between the structure and chiral RTP property but also provides a guide to developing highly efficient chiroptical materials for potential applications.