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‐(10 H ‐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 3.0×10 −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.