Tang Shan-Shun, Yang Guo-Xi, Zhu Jie-Ji, He Xin, Jian Jing-Xin, Lu Feng, Tong Qing-Xiao
Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Material of Guangdong Province, Shantou University, Guangdong, 515063, P.R. China.
Chemistry. 2021 Jun 21;27(35):9102-9111. doi: 10.1002/chem.202100717. Epub 2021 May 19.
Efficient multifunctional materials acting as violet-blue emitters, as well as host materials for phosphorescent OLEDs, are crucial but rare due to demand that they should have high first singlet state (S ) energy and first triplet state (T ) energy simultaneously. In this study, two new violet-blue bipolar fluorophores, TPA-PI-SBF and SBF-PI-SBF, were designed and synthesized by introducing the hole transporting moiety triphenylamine (TPA) and spirobifluorene (SBF) unit that has high T into high deep blue emission quantum yield group phenanthroimidazole (PI). As the results, the non-doped OLEDs based on TPA-PI-SBF exhibited excellent EL performance with a maximum external quantum efficiency (EQE ) of 6.76 % and a violet-blue emission with Commission Internationale de L'Eclairage (CIE) of (0.152, 0.059). The device based on SBF-PI-SBF displayed EQE of 6.19 % with CIE of (0.159, 0.049), which nearly matches the CIE coordinates of the violet-blue emitters standard of (0.131, 0.046). These EL performances are comparable to the best reported non-doped deep or violet-blue emissive OLEDs with CIEy<0.06 in recent years. Additionally, the green, yellow and red phosphorescent OLEDs with TPA-PI-SBF and SBF-PI-SBF as host materials achieved a high EQE of about 20 % and low efficiency roll-off at the ultra-high luminance of 10 000 cd m . These results provided a new construction strategy for designing high-performance violet-blue emitters, as well as efficient host materials for phosphorescent OLEDs.
作为紫蓝色发光体以及用于磷光有机发光二极管（OLED）的主体材料的高效多功能材料至关重要，但由于要求它们应同时具有较高的第一单线态（S）能量和第一三线态（T）能量，这类材料很罕见。在本研究中，通过将空穴传输部分三苯胺（TPA）和具有高T的螺二芴（SBF）单元引入到具有高深蓝色发射量子产率的菲并咪唑（PI）基团中，设计并合成了两种新型紫蓝色双极荧光团TPA-PI-SBF和SBF-PI-SBF。结果表明，基于TPA-PI-SBF的非掺杂OLED表现出优异的电致发光（EL）性能，最大外量子效率（EQE）为6.76%，发射紫蓝色光，国际照明委员会（CIE）坐标为（0.152, 0.059）。基于SBF-PI-SBF的器件显示EQE为6.19%，CIE坐标为（0.159, 0.049），几乎与紫蓝色发光体标准的CIE坐标（0.131, 0.046）相匹配。这些EL性能与近年来报道的CIEy<0.06的最佳非掺杂深或紫蓝色发光OLED相当。此外，以TPA-PI-SBF和SBF-PI-SBF作为主体材料的绿色、黄色和红色磷光OLED在10000 cd·m的超高亮度下实现了约20%的高EQE和低效率滚降。这些结果为设计高性能紫蓝色发光体以及用于磷光OLED的高效主体材料提供了一种新的构建策略。
