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 (gEL) 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 |gEL| value of 0.014.