Synthesis and physical properties of meta-terphenyloxadiazole derivatives and their application as electron transporting materials for blue phosphorescent and fluorescent devices
作者:Cheng-An Wu、Ho-Hsiu Chou、Cheng-Hung Shih、Fang-Iy Wu、Chien-Hong Cheng、Heh-Lung Huang、Teng-Chih Chao、Mei-Rurng Tseng
DOI:10.1039/c2jm33376g
日期:——
Two m-terphenyloxadiazole-based electron transporting materials, bis(2-tert-butyl-1,3,4-oxadiazole-5-diyl)-3,3′-m-terphenyl (tOXD-mTP) and bis(2-(4-tert-butylphenyl)-1,3,4-oxadiazole-5-diyl)-3,3′-m-terphenyl (tpOXD-mTP) were synthesized and characterized. These two molecules contained two oxadiazolyl groups and a m-terphenyl linkage as the core structure achieving high triplet energy gaps (ET) of 2.83 and 2.90 eV, respectively. The application of tOXD-mTP and tpOXD-mTP as the electron transporting materials (ETM) in bis(4′,6′-difluorophenylpyridinato)-iridium(III) picolinate (FIrpic)-based blue phosphorescent light-emitting devices effectively confines the triplet exciton in the emitting layers. One of the electroluminescent (EL) devices using FIrpic as the dopant showed an excellent current efficiency of 43.3 cd A−1 and an external quantum efficiency (EQE) of 23.0% with CIE (Commission International de l'Eclairage) coordinates of (0.13, 0.29). The bis(4′,6′-difluorophenylpyridinato)-iridium(III) tetra(1-pyrazolyl)borate (FIr6)-based deeper blue EL device exhibited a high current efficiency of 42.5 cd A−1 and external quantum efficiency of 25.0% with CIE coordinates of (0.14, 0.23). These two tOXD-mTP and tpOXD-mTP based devices show device efficiencies two to three times higher than that based on the well-known electron transporting material 1,3-bis[(4-tertbutylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD-7).
合成并表征了两种基于m-三苯氧噻唑的电子传输材料,分别是双(2-tert-丁基-1,3,4-氧噻唑-5-基)-3,3′-m-三苯 (tOXD-mTP) 和双(2-(4-tert-丁基苯基)-1,3,4-氧噻唑-5-基)-3,3′-m-三苯 (tpOXD-mTP)。这两种分子均包含两个氧噻唑基团和一个m-三苯链作为核心结构,分别实现了高达2.83和2.90 eV的三重态能量间隙 (ET)。在以双(4′,6′-二氟苯基吡啶)-铱(III)吡咯酸盐 (FIrpic) 为基础的蓝色磷光发光器件中,tOXD-mTP 和 tpOXD-mTP 作为电子传输材料 (ETM) 的应用有效地限制了激发态三重态在发光层中的存在。其中一个使用FIrpic作为掺杂剂的电致发光 (EL) 器件显示出优异的电流效率为43.3 cd A−1,外量子效率 (EQE) 为23.0%,CIE(国际照明委员会)坐标为(0.13, 0.29)。基于双(4′,6′-二氟苯基吡啶)-铱(III)四(1-吡唑基)硼酸盐 (FIr6) 的更深蓝色EL器件展现出42.5 cd A−1的高电流效率和25.0%的外量子效率,CIE坐标为(0.14, 0.23)。这两种以tOXD-mTP和tpOXD-mTP为基础的器件效率是基于著名电子传输材料1,3-双[(4-tert-丁基苯基)-1,3,4-氧噻唑基]苯 (OXD-7) 的两到三倍。