Axially chiral biphenoxazine-based thermally activated delayed fluorescence materials for solution-processed circularly polarized organic light-emitting diodes

Circularly polarized organic light-emitting diodes (CP-OLEDs) from pure organic thermally activated delayed fluorescence (TADF) materials are a research hotspot due to their low price and high electroluminescence efficiency for antiglare filters and 3D displays. Herein, one pair of intrinsically chiral octahydro-binaphthalenes-based biphenoxazine dyes were designed, prepared, and characterized. Bearing one axially chiral electron-donor (D) biphenoxazine core and two electron-acceptor (A) 2,4,6-triphenyl-s-triazineine fragments, they are tri-propeller-type, which would be in favour of both charge separation and A-D-D-A charge transfer to achieve aggregation-induced yellow-green TADF with a quantum yield of 25.2% and 57.6% for neat and doped film, respectively. Most importantly, they can be acted as emitters in solution processed CP-OLEDs to achieve luminance, current efficiency, external quantum efficiency, and dissymmetry factor up to 1.66 × 104 cd/m−2, 35.2 cd/A, 11.3% and 0.88 × 10−3, respectively. Moreover, the dissymmetry factor can be further enhanced to 1.69 × 10−3, if semitransparent electrodes are adopted.