Abstract
By connecting tercarbazole (3Cz) and triphenyltriazine (TRz) units with a diphenyl ether group, we designed and synthesized a new donor-spacer-acceptor structure molecule 9′-(4-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenoxy) phenyl)-9′H-9,3′:6′,9″-tercarbazole (3Cz-o-TRz) as the multifunctional component of exciplex emitters. As expected, the intermolecular charge-transfer transition is dominant for 3Cz-o-TRz because of the space-enough and conjugation-forbidden linkage of the diphenyl ether group, increasing the intrinsic characteristics of the 3Cz and TRz moieties in its single-molecule state. Accordingly, three common electron acceptors (4,6-bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PyMPm), 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-methylpyrimidine (B4PyMPm), and (1,3,5-triazine-2,4,6-triyl) tris(benzene-3,1-diyl)tris(diphenylphosphineoxide) (POT2T)) and three common electron donors (4,4′-(cyclohexane-1,1-diyl)bis(N, N-di-p-tolylaniline) (TAPC), tris(4-(10H-phenoxazin-10-yl)phenyl)amine (TPA-PXZ), and N1-phenyl-N4, N4-bis(4-(phenyl(m-tolyl)amino)phenyl)-N1-(m-tolyl)benzene-1,4-diamine (m-MTDATA)) were chosen to construct six exciplex emitters with 3Cz-o-TRz. In the organic light-emitting diodes (OLEDs), the emission spectra of these exciplex emitters could be gradually modulated from 510 to 590 nm. In addition, TAPC:3Cz-o-TRz- and 3Cz-o-TRz:PO-T2T-based OLEDs achieved desirable performance with maximum external quantum efficiencies (EQEs) around 12%. Moreover, a simple tandem OLED containing TAPC:3Cz-o-TRz and 3Cz-o-TRz:PO-T2T emitters realized optimal performance with an ultralow turn-on voltage of 2.4 V and a maximum EQE of 14.1%. These results indicate the great potential of the donor-spacer-acceptor structure compounds in developing exciplex emitters.
摘要
为了实现高效的激基复合物发光二极管(OLED), 我们设计并合成了一种新型给体-间隔基-受体(D-Spacer-A)结构分子3Cz-o-TRz. 通过引入二苯醚基团作为间隔基, 可以有效地抑制3Cz-o-TRz分子内的电荷转移过程, 使其在单分子态下能够同时表现出给体和受体片段的本征特性, 从而能够作为多功能组分来构建激基复合物. 基于此, 3Cz-o-TRz分别与不同的受体材料和给体材料结合, 构建了六种激基复合物发光分子. 其中, 基于3Cz-o-TRz分别作为给体和受体组分所构建的激基复合物OLED器件均实现了最大外部量子效率(EQE)约为12%的性能. 并且, 通过串联激基复合物TAPC:3Cz-o-TRz和3Cz-o-TRz:PO-T2T为发光分子进一步提高了器件性能, 最大EQE可达14.1%. 我们的工作证明了具有D-Spacer-A结构的分子在构建激基复合物OLED中具有巨大潜力.
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Acknowledgements
This work was supported by the National Natural Science Foundation of China (51773029, 52073040, 51533005 and 51821002), the Fundamental Research Funds for the Central Universities (ZYGX2016Z010), and the International Cooperation and Exchange Project of Science and Technology Department of Sichuan Province (2019YFH0057 and 2019YFH0059).
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Author contributions Zheng CJ and Zhang XH conceived and supervised the project. Yang HY and Shi YZ designed and synthesized the molecule. Yang HY, Zhang M, and Zhao JW prepared the device and performed the corresponding measurements and characterizations. Yang HY and Pu CP performed the data analysis. Yang HY wrote the paper with support from Zheng CJ. All authors contributed to the general discussion.
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Supplementary information Experimental details and supporting data are available in the online version of the paper.
Hao-Yu Yang is a PhD student of the Organic Optoelectronic Laboratory at the University of Electronic Science and Technology of China. His research focuses on the organic optoelectronic materials and devices, mainly on the design, synthesis, manufacture, and characterization of thermally activated delayed fluorescent and exciplex materials for OLEDs.
Cai-Jun Zheng was born in 1984. He received his BSc degree from the Department of Chemistry, Tsinghua University in 2005, and PhD degree from Technical Institute of Physics and Chemistry, Chinese Academy of Sciences in 2010. He joined the University of Electronic Science and Technology of China as a professor in 2016. Currently his interest mainly focuses on the organic optoelectronic materials and devices.
Xiao-Hong Zhang was born in 1967. He received his BSc and MSc degrees from the Department of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics in 1989 and 1992, and PhD degree from the Department of Chemical Engineering and Materials Science, Beijing University of Technology in 1996. He joined Soochow University as a professor in 2013. His current interests mainly focus on organic optoelectronic materials and devices and semiconductor nano-materials and devices.
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Yang, HY., Zheng, CJ., Zhang, M. et al. Novel donor-spacer-acceptor compound as the multifunctional component of exciplexes for efficient organic light-emitting diodes. Sci. China Mater. 65, 460–468 (2022). https://doi.org/10.1007/s40843-021-1752-7
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DOI: https://doi.org/10.1007/s40843-021-1752-7