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Achieving 21% External Quantum Efficiency for Nondoped Solution-Processed Sky-Blue Thermally Activated Delayed Fluorescence OLEDs by Means of Multi-Donor/Acceptor Emitter with Through-Space/-Bond Charge Transfer

Zheng, Xujun; Huang, Rongjuan; Zhong, Cheng; Xie, Guohua; Ning, Weimin; Huang, Manli; Ni, Fan; Dias, Fernando B.; Yang, Chuluo

Achieving 21% External Quantum Efficiency for Nondoped Solution-Processed Sky-Blue Thermally Activated Delayed Fluorescence OLEDs by Means of Multi-Donor/Acceptor Emitter with Through-Space/-Bond Charge Transfer Thumbnail


Authors

Xujun Zheng

Rongjuan Huang

Cheng Zhong

Guohua Xie

Weimin Ning

Manli Huang

Fan Ni

Chuluo Yang



Abstract

Although numerous thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have been demonstrated, the efficient blue or even sky-blue TADF-based non-doped solution-processed devices are still very rare. Herein, we skilfully incorporate through-space charge transfer (TSCT) and through-bond charge transfer (TBCT) effect, as well as the multi-(donor/acceptor) characteristic into one molecule. The former allows this material to show small singlet-triplet energy splitting (ΔEST) and high transition dipole moment. The latter, on one hand, further lights up multi-channel reverse intersystem crossing (RISC) to increase triplet exciton utilization via degenerating molecular orbitals. On the other hand, the nature of the molecular twisted structure effectively suppresses intermolecular packing to obtain high PLQY in neat flims. Consequently, using this design strategy, T-CNDF-T-tCz containing three donor and three acceptor units, successfully realizes an extremely small ΔEST (~ 0.03 eV) and a high PLQY (~ 0.76) at the same time, hence the non-doped solution-processed sky-blue TADF-OLED displays record-breaking efficiency among the solution processes-based non-doped sky-blue OLEDs, with high brightness over 5200 cd m−2 , current efficiency up to 46.4 cd A−1 , and external quantum efficiency up to 21.0%.

Citation

Zheng, X., Huang, R., Zhong, C., Xie, G., Ning, W., Huang, M., …Yang, C. (2020). Achieving 21% External Quantum Efficiency for Nondoped Solution-Processed Sky-Blue Thermally Activated Delayed Fluorescence OLEDs by Means of Multi-Donor/Acceptor Emitter with Through-Space/-Bond Charge Transfer. Advanced Science, 7(7), Article 1902087. https://doi.org/10.1002/advs.201902087

Journal Article Type Article
Acceptance Date Jan 8, 2020
Online Publication Date Feb 8, 2020
Publication Date Apr 8, 2020
Deposit Date Jan 14, 2020
Publicly Available Date Jan 15, 2020
Journal Advanced Science
Publisher Wiley Open Access
Peer Reviewed Peer Reviewed
Volume 7
Issue 7
Article Number 1902087
DOI https://doi.org/10.1002/advs.201902087

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Copyright Statement
© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.







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