Efficient Cyan Delayed Fluorescence Luminogen as Sensitizing Host for OLEDs with High Efficiencies and Extremely Low Roll-Offs

Jianghui Wang; Ruishan Huang; Hao Liu; Hao Chen; Junchu He; Ben Zhong Tang; Zujin Zhao

doi:10.1002/asia.202300076

Efficient Cyan Delayed Fluorescence Luminogen as Sensitizing Host for OLEDs with High Efficiencies and Extremely Low Roll-Offs

Chem Asian J. 2023 May 2;18(9):e202300076. doi: 10.1002/asia.202300076. Epub 2023 Mar 10.

Authors

Jianghui Wang¹, Ruishan Huang¹, Hao Liu¹, Hao Chen¹, Junchu He¹, Ben Zhong Tang², Zujin Zhao¹

Affiliations

¹ State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China.
² School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China.

PMID: 36856761
DOI: 10.1002/asia.202300076

Abstract

Organic light-emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF) materials to sensitizing conventional fluorescence dopants (CFDs) have attracted intensive research interest due to the extraordinary device performances. Herein, a cyan luminogen (TCz-BP-SFAC) with TADF and aggregation-enhanced emission (AEE) character is developed as a sensitizing host for CFDs. TCz-BP-SFAC owns excellent thermal and electrochemical stabilities, prefers horizontal dipole orientation and demonstrates violent delayed fluorescence with high photoluminescence quantum yields in neat and doped films. It exhibits preeminent electroluminescence (EL) performances with maximum external quantum efficiencies (η_ext s) of 25.1% and 30.0% and very low efficiency roll-offs. TCz-BP-SFAC also performs well as a sensitizing host for CFDs of different colors. When TCz-BP-SFAC sensitizing green emitter TTPA and orange emitter TBRB, the devices achieve high η_ext s of 16.9% and 17.1% as well as very low efficiency roll-offs of 2.4% and 1.2%, respectively. Moreover, TCz-BP-SFAC can serve as a sensitizing host for two-color all-fluorescence white OLEDs, resulting in high η_ext s of ∼18% and very low efficiency roll-offs of ∼5%. The outstanding EL performances predict the great potential of TCz-BP-SFAC as emitter and host in practical display and lighting devices.

Keywords: aggregation-enhanced emission; efficiency roll-off; organic light-emitting diode; sensitizing host; thermally activated delayed fluorescence.

Abstract

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