Abstract: Realizing blue-hazard-free emission is an important goal for white organic light-emitting diodes (OLEDs) toward healthy lighting applications. However, conventional blue organic emitters with broad emission spectra would generally cover the high-energy emission region and thus cannot meet the demand. Here a blue multiple resonance type thermally activated delayed fluorescence (TADF) emitter DPMX-CzDABNA is newly designed. The DPMX-CzDABNA-based OLEDs can realize blue narrowband emission peaked at 484 nm with a full width at half maximum of 29 nm, and external quantum efficiencies (EQEs) around 26%, which allows DPMX-CzDABNA to precisely avoid the high-energy photon contribution and thus be a promising blue component to construct high-performance white OLEDs with human-eye-friendly emission spectra. Using DPMX-CzDABNA and a reported TADF emitter BPPZ-DPXZ, respectively, as blue and orange components in white OLEDs, the single-emitting-layer devices approach white emission with outstanding EQE up to 35.8%; the double-emitting-layer OLEDs achieve blue-hazard-free white emissions with a maximum EQE of 26.5% and very stable Commission Internationale de l'Eclairage coordinates of ≈(0.38,0.43) over a wide luminance range from 100 to 10 000 cd m−2. It is expected that this strategy can pave a new way for developing highly efficient all-TADF white OLEDs without blue-hazard emission.
链接：https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202202267
