Aromatic-imide-based TADF enantiomers for efficient circularly polarized electroluminescence

Recently, much attention has been paid to circularly polarized organic light-emitting diodes (CP-OLEDs) based on thermally activated delayed fluorescence (TADF) enantiomers. In this paper, we designed and synthesized a pair of aromatic-imide-based TADF enantiomers, namely R/S-OBN-AICz, using chiral perturbation strategy. The chiral emitters concurrently demonstrated efficient TADF and aggregation-induced emission (AIE) properties, together with a small singlet-triplet energy gap (Delta E-ST) of 0.08 eV and a high photoluminescence quantum yield (PLQY) of 81%. Moreover, the TADF enantiomers exhibited clear circularly polarized luminescence (CPL) activities with dissymmetry factor (vertical bar g(PL vertical bar)) values of up to 2.6 x 10(-3) in toluene solution. Finally, the TADF enantiomers were utilized as emitters to fabricate CP-OLEDs, which achieved clear circularly polarized electroluminescence (CPEL) signals, a high maximum external quantum efficiency (EQE(max)) of 19.0% and a high maximum luminance (L-max) of 24 790 cd m(-2).

Automated summary

In this study, a pair of chiral emitters with efficient TADF and AIE properties were designed and synthesized, and successfully applied in the fabrication of CP-OLEDs, achieving high circularly polarized electroluminescence performance.