biostudies-literatureKrotkus SNational Research Foundation of KoreaEuropean CommissionEngineering and Physical Sciences Research Council572862https://www.ebi.ac.uk/biostudies/studies/S-EPMC7817954biostudies-literatureUnknown8Three novel donor-acceptor molecules comprising the underexplored pyridazine (Pydz) acceptor moiety have been synthesized and their structural, electrochemical and photophysical properties thoroughly characterized. Combining Pydz with two phenoxazine donor units linked via a phenyl bridge in a <i>meta</i> configuration (<b>dPXZMePydz</b>) leads to high reverse intersystem crossing rate <i>k</i> _RISC = 3.9 · 10⁶ s^-1 and fast thermally activated delayed fluorescence (TADF) with <500 ns delayed emission lifetime. Efficient triplet harvesting via the TADF mechanism is demonstrated in OLEDs using <b>dPXZMePydz</b> as the emitter but does not occur for compounds bearing weaker donor units.Frontiers in chemistryFast Delayed Emission in New Pyridazine-Based Compounds.PMC7817954EP/L017008/1EP/P010482/1EP/R035164/1Gather MCCopley GSlawin AMZKrotkus SMatulaitis TArcher EDiesing SKeum CZysman-Colman ECordes DBSamuel IDWfalseFast Delayed Emission in New Pyridazine-Based Compounds.Three novel donor-acceptor molecules comprising the underexplored pyridazine (Pydz) acceptor moiety have been synthesized and their structural, electrochemical and photophysical properties thoroughly characterized. Combining Pydz with two phenoxazine donor units linked via a phenyl bridge in a <i>meta</i> configuration (<b>dPXZMePydz</b>) leads to high reverse intersystem crossing rate <i>k</i> _RISC = 3.9 · 10⁶ s^-1 and fast thermally activated delayed fluorescence (TADF) with <500 ns delayed emission lifetime. Efficient triplet harvesting via the TADF mechanism is demonstrated in OLEDs using <b>dPXZMePydz</b> as the emitter but does not occur for compounds bearing weaker donor units.2020-01-01T00:00:00Z20202026-04-07T15:03:59.397Z2021-02-21T03:08:58ZS-EPMC78179543349003110.3389/fchem.2020.572862