Asymmetric donor-acceptor-host red thermally activated delayed fluorescent emitter for high-efficiency organic light emitting diodes

Efficient red emitters are crucial to the widespread use of organic light-emitting diodes (OLEDs) in future display and lighting technologies. However, the highly planar configurations of red TADF emitters lead to intermolecular-interaction-induced quenching. To obtain highly efficient doping-insens...

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Bibliographic Details
Published in:Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2023-07, Vol.11 (27), p.9348-9354
Main Authors: Li, Hao-Ze, Xie, Feng-Ming, Wu, Ping, Zhang, Kai, Zhao, Xin, Li, Yan-Qing, Tang, Jian-Xin
Format: Article
Language:English
Subjects:
Anthraquinones
Asymmetry
Benzene
Doping
Electrons
Emitters
Fluorescence
Material properties
Organic light emitting diodes
Photoluminescence
Quantum efficiency
Quenching
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Summary:Efficient red emitters are crucial to the widespread use of organic light-emitting diodes (OLEDs) in future display and lighting technologies. However, the highly planar configurations of red TADF emitters lead to intermolecular-interaction-induced quenching. To obtain highly efficient doping-insensitive red emitters, a novel asymmetric red thermally activated delayed fluorescence (TADF) emitter, TPA-AQ-DCP , was developed using an asymmetric donor-acceptor-host (D-A-H) structure. The material consists of anthraquinone as the acceptor, triphenylamine as the donor, and 1,4-di(9 H -carbazol-9-yl)benzene (DCP) serving as part of the emitter with host material properties. It is demonstrated that incorporating the host group into the TADF emitter with asymmetrical structure improves electron and hole transport within the emitter, effectively reducing concentration quenching. As a consequence, the asymmetric D-A-H structured TPA-AQ-DCP exhibited a relatively high photoluminescent quantum yield (PLQY) of 79.2% and fast radiative rate constant ( k r ) of 6.60 × 10 7 s −1 , and thus better EL performance. Consequently, an efficient external quantum efficiency (EQE) of 11.76-17.60% with an emission peak of 610-620 nm was achieved for the TPA-AQ-DCP -based devices with doping ratios ranging from 5 wt% to 25 wt%. A new asymmetric D-A-H type TADF emitter, TPA-AQ-DCP , is designed to improve exciton utilization and restrict intermolecular interactions in OLEDs with red emission and efficiency of up to 17.60%.
ISSN:2050-7526
2050-7534
DOI:10.1039/d3tc01632c