Non-doped and doped circularly polarized organic light-emitting diodes with high performances based on chiral octahydro-binaphthyl delayed fluorescent luminophores

Abstract

Circularly polarized organic light-emitting diodes (CP-OLEDs) are of great value for facilitating the development of next generation display technologies, especially for implementing real 3D displays. However, most CP-OLEDs have insufficient efficiency and serious efficiency roll-off. In this study, a pair of octahydro-binaphthyl (OBN)-based chiral emitting enantiomers, (R/S)-OBN-DPA, were synthesized by ingeniously merging the chiral source and the luminophore skeleton of cyan and diphenylamine groups. The chirality–acceptor–donor (C–A–D) type enantiomers concurrently demonstrate a high photoluminescence quantum yield of 84.67%, and intense circularly polarized photoluminescence with dissymmetry factors (|g_PL|) around 2.0 × 10⁻³ in the films. The non-doped and doped CP-OLEDs achieve markedly circularly polarized electroluminescence signals with |g_EL| up to 2.9 × 10⁻³, high brightness over 25 000 cd cm⁻², high efficiency with a maximum external quantum efficiency (EQE_max) of 12.4%, and negligible efficiency roll-off with an EQE of 11.5% at a practical luminance of 1000 cd m⁻², which are the best results among the reported CP-devices to date.