Multi-resonance emitters (MREs) are a promising candidate for fulfilling the harsh requirements of display applications due to their unique photophysical properties. Recently, MREs have been widely used as a terminal emitter in hyperfluorescence organic light-emitting diodes (HF-OLEDs); however, since MREs are always thermally activated delayed fluorescence (TADF)-active, possessing long triplet lifetimes in millisecond order, they result in severe chemical degradation. Instead of shortening the delayed lifetime of MREs by molecular design, herein, a low-triplet pyrene unit is introduced into an MRE scaffold to achieve narrowband emission and quick removal of triplets in MREs simultaneously. Blue HF-OLED based on the non-TADF MRE demonstrates a high external quantum efficiency of 20% and a tenfold improvement in stability, compared to those of the HF-OLEDs with standard MREs. An opposite direction of molecular design of MREs for the sophisticated exciton generation and transfer system in HF-OLEDs is proposed to enhance device lifetime without sacrificing color purity and efficiency.
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