Islam Amjad, Zhang Dongdong, Peng Ruixiang, Yang Rongjuan, Hong Ling, Song Wei, Wei Qiang, Duan Lian, Ge Ziyi
Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, 315201, P.R. China.
Academy of Sciences, University of Chinese, Beijing, 100049, P.R. China.
Chem Asian J. 2017 Sep 5;12(17):2189-2196. doi: 10.1002/asia.201700833. Epub 2017 Aug 4.
Blue organic light-emitting diodes (OLEDs) are necessary for flat-panel display technologies and lighting applications. To make more energy-saving, low-cost and long-lasting OLEDs, efficient materials as well as simple structured devices are in high demand. However, a very limited number of blue OLEDs achieving high stability and color purity have been reported. Herein, three new sky-blue emitters, 1,4,5-triphenyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole (TPEI), 1-(4-methoxyphenyl)-4,5-diphenyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole (TPEMeOPhI) and 1-phenyl-2,4,5-tris(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole (3TPEI), with a combination of imidazole and tetraphenylethene groups, have been developed. High photoluminescence quantum yields are obtained for these materials. All derivatives have demonstrated aggregation-induced emission (AIE) behavior, excellent thermal stability with high decomposition and glass transition temperatures. Non-doped sky-blue OLEDs with simple structure have been fabricated employing these materials as emitters and realized high efficiencies of 2.41 % (4.92 cd A , 2.70 lm W ), 2.16 (4.33 cd A , 2.59 lm W ) and 3.13 % (6.97 cd A , 4.74 lm W ) for TPEI, TPEMeOPhI and 3TPEI, with small efficiency roll-off. These are among excellent results for molecules constructed from the combination of imidazole and TPE reported so far. The high performance of a 3TPEI-based device shows the promising potential of the combination of imidazole and AIEgen for synthesizing efficient electroluminescent materials for OLED devices.
蓝色有机发光二极管（OLED）对于平板显示技术和照明应用至关重要。为了制造更节能、低成本且持久的OLED，高效材料以及结构简单的器件备受需求。然而，据报道能够实现高稳定性和色纯度的蓝色OLED数量非常有限。在此，合成了三种新型天蓝色发光体，即1,4,5-三苯基-2-(4-(1,2,2-三苯基乙烯基)phenyl)-1H-咪唑（TPEI）、1-(4-甲氧基苯基)-4,5-二苯基-2-(4-(1,2,2-三苯基乙烯基)phenyl)-1H-咪唑（TPEMeOPhI）和1-苯基-2,4,5-三(4-(1,2,2-三苯基乙烯基)phenyl)-1H-咪唑（3TPEI），它们是咪唑和四苯乙烯基团的组合。这些材料具有高光致发光量子产率。所有衍生物均表现出聚集诱导发光（AIE）行为、具有高分解温度和玻璃化转变温度的优异热稳定性。以这些材料作为发光体制造了结构简单的非掺杂天蓝色OLED，TPEI、TPEMeOPhI和3TPEI的器件分别实现了2.41%（4.92 cd A ，2.70 lm W ）、2.16%（4.33 cd A ，2.59 lm W ）和3.13%（6.97 cd A ，4.74 lm W ）的高效率，且效率滚降较小。这些是迄今为止由咪唑和TPE组合构建的分子所取得的优异结果之一。基于3TPEI的器件的高性能表明，咪唑和聚集诱导发光体（AIEgen）的组合在合成用于OLED器件的高效电致发光材料方面具有广阔的潜力。
