Circularly Polarized White Organic Light-Emitting Diodes Based on Spiro-Type Thermally Activated Delayed Fluorescence Materials

In this study, we report the first circularly polarized white organic light-emitting diodes (CP-WOLEDs) based on all thermally activated delayed fluorescence (TADF) materials. Two pairs of spiro-type TADF enantiomers, (R/S)-SPOCN (5,5 '-((2,2 ',3,3 '-tetrahydro-1,1 '-spirobi[indene]-7,7 '-diyl)bis(oxy))bis(4-(10H-phenoxazin-10-yl)phthalonitrile)) and (R/S)-OSFSO (2 '-(trifluoromethyl)-spiro[quinolino[3,2,1-kl]phenoxazine-9,9 '-thioxanthene]-10 ',10 '-dioxide), serve as emitters with complementary emission. The CP-OLEDs exhibit warm white emission with a CIE coordinate of (0.35, 0.46). Besides, decent device performances are observed with an external quantum efficiency of up to 21.6 % at maximum and 11.8 % at 1000 cd m(-2). Obvious circularly polarized electroluminescence signals are detected with a dissymmetry factor |g(EL)| of around 3.0x10(-3). This is the first report of CP-WOLEDs that can harvest both singlet and triplet excitons, which provides a feasible strategy for the development of CP-WOLEDs with remarkable device performances.

Automated summary

In this study, we introduce the first circularly polarized white organic light-emitting diodes (CP-WOLEDs) based on all thermally activated delayed fluorescence (TADF) materials. These CP-OLEDs exhibit excellent device performances and warm white emission.