Stimuli-Responsive Aggregation-Induced Delayed Fluorescence Emitters Featuring the Asymmetric D-A Structure with a Novel Diarylketone Acceptor Toward Efficient OLEDs with Negligible Efficiency Roll-Off

Zhiwen Yang; Yingying Zhan; Zhipeng Qiu; Jiajie Zeng; Jingjing Guo; Sheng Hu; Zujin Zhao; Xianwei Li; Shaomin Ji; Yanping Huo; Shi-Jian Su

doi:10.1021/acsami.0c07612

Stimuli-Responsive Aggregation-Induced Delayed Fluorescence Emitters Featuring the Asymmetric D-A Structure with a Novel Diarylketone Acceptor Toward Efficient OLEDs with Negligible Efficiency Roll-Off

ACS Appl Mater Interfaces. 2020 Jul 1;12(26):29528-29539. doi: 10.1021/acsami.0c07612. Epub 2020 Jun 22.

Authors

Zhiwen Yang¹, Yingying Zhan¹, Zhipeng Qiu¹, Jiajie Zeng², Jingjing Guo², Sheng Hu¹, Zujin Zhao², Xianwei Li¹, Shaomin Ji¹, Yanping Huo^{1

3}, Shi-Jian Su²

Affiliations

¹ School of Chemical Engineering & Light Industry, Guangdong University of Technology, 510006 Guangzhou, China.
² State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 510640 Guangzhou, China.
³ Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, 510640 Guangzhou, China.

PMID: 32508095
DOI: 10.1021/acsami.0c07612

Abstract

Multifunctional luminescent materials with aggregation-induced delayed fluorescence (AIDF) are capable of suppressing concentration-caused emission quenching and exciton annihilation when used as organic light-emitting diode (OLED) emitters. In this contribution, three stimuli-responsive AIDF luminogens, pipd-BZ-PXZ, pipd-BZ-PTZ, and pipd-BZ-DMAC, featuring a D-A asymmetric framework based on a fused N-heterocycle diarylketone acceptor (imid-azo[1,2-a]pyridin-2-yl(phenyl)methanone pipd) are designed and synthesized. Interestingly, pipd-BZ-PTZ forms two different kinds of crystals (G-crystal and O-crystal) with distinct intermolecular interactions between pipd moieties. The G-crystal with a looser packing mode presents significant morphology-dependent stimuli-responsive behavior with a shifted emission wavelength of 56 nm. Generated by a strong intramolecular charge transfer effect, pipd-BZ-PXZ and pipd-BZ-PTZ exhibit orange to red emission in solution and neat films. Both nondoped and doped devices are fabricated for comparison. Nondoped devices present moderate performance with external quantum efficiencies and current efficiency that reach 7.04% and 19.86 cd A^-1, respectively, and the corresponding efficiency roll off at 1000 cd m^-2 is as small as 2.3%, which is among the best records of AIDF-OLEDs with an emission wavelength over 570 nm. Doped devices show better performance with corresponding efficiencies of up to 55.41 cd A^-1 and 15.77%.

Keywords: aggregation-induced delayed fluorescence; diaryketone acceptor; organic light-emitting diodes; stimuli-responsive; thermally activated delayed fluorescence.