Highly efficient deep-blue organic electroluminescent devices doped with hexaphenylanthracene fluorophores
作者:Sheng-Hsun Lin、Fang-Iy Wu、Hsiu-Yun Tsai、Pei-Yu Chou、Ho-Hsiu Chou、Chien-Hong Cheng、Rai-Shung Liu
DOI:10.1039/c1jm10424a
日期:——
Fluorescent 2,3,6,7,9,10-hexaphenylanthracene-based derivatives (HPhAn) were synthesized to serve as deep-blue dopants in organic electroluminescent (EL) devices. The fluorescent emissions of HPhAn fluorophores, fine-tuned from 462 to 449 nm with varied fluorinated phenyl rings attached to the central carbons of the anthracene core, produced photoluminescence quantum yields of 82–88% in the solid state. Unlike the known monostyrylamine deep-blue dopant, these blue dopants in dilute solutions showed no pronounced spectral red shift with increasing solvent polarity; the emission color of HPhAn dopants is thus insensitive to the polarity of the medium. The highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) energy levels calculated from the oxidation potentials and optical energy gaps are 5.61–5.70 eV and 2.73–2.89 eV, respectively. These thermally robust compounds undergo thermal decomposition at temperatures greater than 300 °C. The relationships among current density, voltage and luminance, the EL efficiency and the operational stability of devices based on the blue HPhAn dopants were examined. These HPhAn-doped EL devices are activated at voltages less than 3.5 V and attained an external quantum efficiency as much as 5.3% in the deep-blue light region with Commission Internationale d'Éclairage (CIE) coordinates (0.14, 0.10), near the National Television System Committee (NTSC) standard blue coordinates (0.14, 0.08).
合成荧光2,3,6,7,9,10-六苯基蒽衍生物(HPhAn)作为有机电致发光(EL)器件中的深蓝色掺杂剂。HPhAn荧光团的荧光发射在固态下产生82-88%的光致发光量子产率,其荧光发射波长在462-449纳米之间微调,通过在蒽核的碳原子中心连接不同的氟苯环。与已知的单苯乙烯胺深蓝色掺杂剂不同,这些蓝色掺杂剂在稀溶液中不会随着溶剂极性的增加而出现明显的光谱红移;因此,HPhAn掺杂剂的发射颜色对介质的极性不敏感。根据氧化电位和光能隙计算出的最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)能量级分别为5.61-5.70 eV和2.73-2.89 eV。这些热稳定性强的化合物在高于300°C的温度下会发生热分解。研究了基于蓝色HPhAn掺杂剂的器件的电流密度、电压和亮度、EL效率和操作稳定性之间的关系。这些HPhAn掺杂的EL器件在电压低于3.5 V时激活,在深蓝色光区域获得了高达5.3%的外量子效率,其国际照明委员会(CIE)坐标(0.14,0