High Comprehensive Circularly Polarized Electroluminescence Performance Improved by Chiral Coassembled Host Materials

Abstract Circularly polarized organic light‐emitting diodes are of great significance in 3D displays. However, achieving circularly polarized electroluminescence (CP‐EL) simultaneously with a large dissymmetry factor (g_EL) and high efficiency still remains a formidable challenge. Herein, a facile and efficient strategy is developed for improving the performance of CP‐EL devices using device emitting layers of chiral coassembled helix nanofiber host materials. Chiral coassembled helix nanofiber host materials ((S‐/R‐2Cz)_0.2‐(PFpy)_0.8) could be smartly constructed through intermolecular π–π stacking interactions between the achiral conjugated pyridine‐based polymer acceptor (PFpy) and the chiral binaphthyl‐based donor (S‐/R‐2Cz). Significantly, the resulting chiral coassembled hosts (S‐/R‐2Cz)_0.2‐(PFpy)_0.8 greatly promote a commercially available achiral phosphorescence emitter to achieve solution‐processed red CP‐EL device performances at 620 nm with a high external quantum efficiency of 4.1% and a large |g_EL| value of 0.014.