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Multi‐Layer π‐Stacked Molecules as Efficient Thermally Activated Delayed Fluorescence Emitters
Author(s) -
Wang XueQi,
Yang ShengYi,
Tian QiSheng,
Zhong Cheng,
Qu YangKun,
Yu YouJun,
Jiang ZuoQuan,
Liao LiangSheng
Publication year - 2021
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.202011384
Subject(s) - intersystem crossing , fluorescence , acceptor , moiety , photoluminescence , singlet state , materials science , molecule , photochemistry , optoelectronics , quantum efficiency , chemistry , optics , atomic physics , physics , excited state , stereochemistry , organic chemistry , condensed matter physics
Multi‐layer π‐stacked emitters based on spatially confined donor/acceptor/donor (D/A/D) patterns have been developed to achieve high‐efficiency thermally activated delayed fluorescence (TADF). In this case, dual donor moieties and a single acceptor moiety are introduced to form two three‐dimensional (3D) emitters, DM‐BD1 and DM‐BD2, which rely on spatial charge transfer (CT). Owing to the enforced face‐to‐face D/A/D pattern, effective CT interactions are realized, which lead to high photoluminescence quantum yields (PLQYs) of 94.2 % and 92.8 % for the two molecules, respectively. The resulting emitters exhibit small singlet–triplet energy splitting (Δ E ST ) and fast reverse intersystem crossing (RISC) processes. Maximum external quantum efficiencies (EQEs) of 28.0 % and 26.6 % were realized for devices based on DM‐BD1 and DM‐BD2, respectively, which are higher than those of their D/A‐type analogues.