Abstract
Green inverted organic light-emitting diodes (OLEDs) based on a thermally activated delayed fluorescent (TADF) emitter, 2-pheyl-4'-carbazole-9-H-thioxanthen-9-one-10,10-dioxide, with a cathode of indium tin oxide (ITO)/ZnO injecting electrons efficiently into the electron transporting layer of Alq3, are demonstrated for the first time. The insertion of 7-nm Cs2CO3 can further enhance the electron injection. The optimized device with 25-nm ZnO and 7-nm Cs2CO3 affords the highest performance of the inverted devices with a current efficiency of 28.1 cd A−1, a power efficiency of 16.1 lm W−1, and an external quantum efficiency of 9.8%. The inverted OLEDs based on TADF emitters are competitive compared with conventional OLEDs because of their air-stable electrodes and TADF emitters, which enable simpler encapsulation.
摘要
本论文首次报道了基于热激活延迟荧光材料TXO-PhCz的倒置结构绿光有机电致发光器件. 器件以ITO/ZnO作为电子注入阴极, 提 高了电子向Alq3层中的有效注入. 7 nm 的Cs2CO3可以进一步提高电子的注入效率. 最优化器件以25-nm ZnO和7-nm Cs2CO3层实现了电子 的有效注入, 器件显示出最佳性能, 器件的电流效率为28.1 cd A−1, 功率为16.1 lmW−1, 外量子效率达9.8%. 基于TADF发光材料的倒向OLEDs 器件由于其电极材料和发光材料的优异稳定性, 可以实现简单封装, 有望替代传统OLEDs.
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Acknowledgments This work was supported by the National Natural Science Foundation of China (61420106002 and 51373189), the “Hundred Talents Program” of the Chinese Academy of Sciences, and the Start-up Fund of the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences.
Author contributions Lv X and Wang Y designed the project, and the experiments. Lv X performed the experiments, and Lv X wrote the paper with support from Wang Y. All authors contributed to the general discussion.
Conflict of interest The authors declare that they have no conflict of interest.
Supplementary information Supplementary data are available in the online version of the paper.
Xiaopeng Lv has been amaster student at the FunctionalNano &SoftMaterials Laboratory, SoochowUniversity since 2013. His research is focused on the construction of high performance organic light-emitting devices.
Ying Wang is a professor at the Key Laboratory of Photochemical Conversion and Optoelectronic Materials at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. His research is focused on the photochemical and photophysical process of organic semiconductors and their application in organic electronics. He have authored and co-authoredmore than 40 international journal publications (including Nat Commun, J Am Chem Soc, AdvMater, Phys Rev Lett, etc.) with more than 1400 citations.
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Lv, X., Wang, H., Meng, L. et al. Highly efficient inverted organic light-emitting diodes based on thermally activated delayed fluorescence. Sci. China Mater. 59, 421–426 (2016). https://doi.org/10.1007/s40843-016-5071-y
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DOI: https://doi.org/10.1007/s40843-016-5071-y