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Donor–σ–Acceptor Motifs: Thermally Activated Delayed Fluorescence Emitters with Dual Upconversion
Author(s) -
Geng Yan,
D'Aleo Anthony,
Inada Ko,
Cui LinSong,
Kim Jong Uk,
Nakanotani Hajime,
Adachi Chihaya
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201708876
Subject(s) - acceptor , photon upconversion , fluorescence , photoluminescence , microsecond , excited state , photochemistry , materials science , singlet state , intramolecular force , förster resonance energy transfer , triplet state , optoelectronics , chemistry , doping , atomic physics , optics , physics , stereochemistry , condensed matter physics
A family of organic emitters with a donor–σ–acceptor (D‐σ‐A) motif is presented. Owing to the weakly coupled D‐σ‐A intramolecular charge‐transfer state, a transition from the localized excited triplet state ( 3 LE) and charge‐transfer triplet state ( 3 CT) to the charge‐transfer singlet state ( 1 CT) occurred with a small activation energy and high photoluminescence quantum efficiency. Two thermally activated delayed fluorescence (TADF) components were identified, one of which has a very short lifetime of 200–400 ns and the other a longer TADF lifetime of the order of microseconds. In particular, the two D‐σ‐A materials presented strong blue emission with TADF properties in toluene. These results will shed light on the molecular design of new TADF emitters with short delayed lifetimes.