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Axially Chiral TADF‐Active Enantiomers Designed for Efficient Blue Circularly Polarized Electroluminescence
Author(s) -
Li Meng,
Wang YinFeng,
Zhang Dongdong,
Duan Lian,
Chen ChuanFeng
Publication year - 2020
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.201914249
Subject(s) - electroluminescence , enantiomer , circular polarization , singlet state , luminescence , intramolecular force , materials science , optoelectronics , physics , chemistry , stereochemistry , optics , excited state , atomic physics , nanotechnology , layer (electronics) , microstrip
The use of a chiral, emitting skeleton for axially chiral enantiomers showing activity in thermally activated delayed fluorescence (TADF) with circularly polarized electroluminescence (CPEL) is proposed. A pair of chiral stable enantiomers, (−)‐( S )‐Cz‐Ax‐CN and (+)‐( R )‐Cz‐Ax‐CN, was designed and synthesized. The enantiomers, both exhibiting intramolecular π‐conjugated charge transfer (CT) and spatial CT, show TADF activities with a small singlet–triplet energy difference (Δ E ST ) of 0.029 eV and mirror‐image circularly polarized luminescence (CPL) activities with large g lum values. Notably, CP‐OLEDs based on the enantiomers feature blue electroluminescence centered at 468 nm with external quantum efficiencies (EQEs) of 12.5 and 12.7 %, and also show intense CPEL with g EL values of −1.2×10 −2 and +1.4×10 −2 , respectively. These are the first CP‐OLEDs based on TADF‐active enantiomers with efficient blue CPEL.