Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P.R. China.
Chemistry. 2018 Jun 7;24(32):8056-8060. doi: 10.1002/chem.201800974. Epub 2018 May 7.
A series of blue-emissive 7-(diphenylamino)-4-phenoxycoumarin derivatives bearing -CF , -OMe, or -N(Me) substituents on the phenoxy subunit were synthesized. Although both the -CF and -N(Me) modifications were found to trigger redshifted fluorescence, the -OMe substitution was demonstrated to exert an unexpected blueshift color-tuning effect toward the deep-blue region. The reason is that the moderate electron-donating -OMe group can endow coumarins with unaltered HOMO but elevated LUMO energy levels. Moreover, the -OMe substitution was found to be beneficial to the thermal stability of these coumarins. Therefore, the trimethoxy-substituted objective compound can act as a high-performance deep-blue organic light-emitting diode (OLED) emitter, and OLED based on it emits deep-blue light with CIE coordinates of (0.148, 0.084), maximum luminance of 7800 cd m , and maximum external quantum efficiency of 5.1 %. These results not only shed light on the molecular design strategy for high-performance deep-blue OLED emitters through color-tuning, but also show the perspective of coumarin derivatives as deep-blue OLED emitters.
一系列在苯氧基取代基上带有-CF 、-OMe 或-N(Me)取代基的蓝色发射 7-(二苯基氨基)-4-苯氧基香豆素衍生物被合成了。尽管 -CF 和 -N(Me) 修饰都被发现引发了红移荧光，但 -OMe 取代基被证明对深蓝光区产生了意想不到的蓝移颜色调谐效应。原因是适度的给电子 -OMe 基团可以赋予香豆素不变的 HOMO 但升高的 LUMO 能级。此外，-OMe 取代基被发现有利于这些香豆素的热稳定性。因此，三甲氧基取代的目标化合物可以作为高性能的深蓝色有机发光二极管（OLED）发射器，基于它的 OLED 发出深蓝光，CIE 坐标为（0.148，0.084），最大亮度为 7800 cd/m ，最大外量子效率为 5.1%。这些结果不仅为通过颜色调谐设计高性能深蓝色 OLED 发射器提供了分子设计策略的启示，而且展示了香豆素衍生物作为深蓝色 OLED 发射器的前景。
