Fast Delayed Emission in New Pyridazine-Based Compounds.

Authors :: Krotkus S
Matulaitis T
Diesing S
Copley G
Archer E
Keum C
Cordes DB
Slawin AMZ
Gather MC
Zysman-Colman E
Samuel IDW
Source :: Frontiers in chemistry [Front Chem] 2021 Jan 07; Vol. 8, pp. 572862. Date of Electronic Publication: 2021 Jan 07 (Print Publication: 2020).
Publication Year :: 2021
Abstract: 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 meta configuration ( dPXZMePydz ) leads to high reverse intersystem crossing rate k <subscript>RISC</subscript> = 3.9 · 10 <superscript>6</superscript> s <superscript>-1</superscript> 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 dPXZMePydz as the emitter but does not occur for compounds bearing weaker donor units.<br />Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.<br /> (Copyright © 2021 Krotkus, Matulaitis, Diesing, Copley, Archer, Keum, Cordes, Slawin, Gather, Zysman-Colman and Samuel.)