Yang Zhiwen, Zhan Yingying, Qiu Zhipeng, Zeng Jiajie, Guo Jingjing, Hu Sheng, Zhao Zujin, Li Xianwei, Ji Shaomin, Huo Yanping, Su Shi-Jian
School of Chemical Engineering & Light Industry, Guangdong University of Technology, 510006 Guangzhou, China.
State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 510640 Guangzhou, China.
ACS Appl Mater Interfaces. 2020 Jul 1;12(26):29528-29539. doi: 10.1021/acsami.0c07612. Epub 2020 Jun 22.
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, -BZ-PXZ, -BZ-PTZ, and -BZ-DMAC, featuring a D-A asymmetric framework based on a fused N-heterocycle diarylketone acceptor (imid-azo[1,2-]pyridin-2-yl(phenyl)methanone ) are designed and synthesized. Interestingly, -BZ-PTZ forms two different kinds of crystals (G-crystal and O-crystal) with distinct intermolecular interactions between 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, -BZ-PXZ and -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, respectively, and the corresponding efficiency roll off at 1000 cd m 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 and 15.77%.
具有聚集诱导延迟荧光（AIDF）的多功能发光材料在用作有机发光二极管（OLED）发光体时，能够抑制浓度引起的发射猝灭和激子湮灭。在本研究中，设计并合成了三种基于稠合N-杂环二芳基酮受体（咪唑并[1,2-a]吡啶-2-基（苯基）甲酮）的具有D-A不对称骨架的刺激响应型AIDF发光剂，即-BZ-PXZ、-BZ-PTZ和-BZ-DMAC。有趣的是，-BZ-PTZ形成了两种不同类型的晶体（G-晶体和O-晶体），其部分之间具有不同的分子间相互作用。具有较松散堆积模式的G-晶体呈现出显著的形态依赖刺激响应行为，发射波长偏移56 nm。由强分子内电荷转移效应产生的-BZ-PXZ和-BZ-PTZ在溶液和纯薄膜中呈现橙色到红色的发射。制备了非掺杂和掺杂器件进行比较。非掺杂器件表现出中等性能，外部量子效率和电流效率分别达到7.04%和19.86 cd/A，并且在1000 cd/m²时相应的效率滚降小至2.3%，这是发射波长超过570 nm的AIDF-OLEDs的最佳记录之一。掺杂器件表现出更好的性能，相应效率高达55.41 cd/A和15.77%。
