Jayabharathi Jayaraman, Sujatha Palanisamy, Thanikachalam Venugopal, Nethaji Pavadai
Department of Chemistry, Annamalai University Annamalainagar 608 002 Tamilnadu India
RSC Adv. 2018 May 31;8(36):20007-20015. doi: 10.1039/c8ra02840k. eCollection 2018 May 30.
Comparative optical, electroluminescence and theoretical studies were performed for ()-4'-(1-(4-(2-(1-(4-morpholinophenyl)-1-phenanthro[9,10-]imidazol-2-yl)vinyl)phenyl)-1-phenanthro[9,10-]imidazol-2-yl)-,-diphenyl-[1,1'-biphenyl]-4-amine (SMPI-TPA) and ()-4-(4-(2-(4-(2-(4-(9-carbazol-9-yl)phenyl)-1-phenanthro[9,10-]imidazol-1-yl)styryl)-1-phenanthro[9,10-]imidazol-1-yl)phenyl)morpholine (SMPI-Cz). These compounds show excellent thermal properties, dual charge transport properties and form thin films under thermal evaporation. Blue OLEDs (CIE: 0.16, 0.08) based on SMPI-TPA show efficient device performance ( 6.1%; 5.3 cd A; 5.2 lm W) at low turn-on voltages. Both SMPI-TPA and SMPI-Cz were utilised as hosts for green OLEDs. The devices with SMPI-Cz (30 nm):5 wt% Ir(ppy) exhibit maximum luminance of 20 725 cd m, and and values of 61.4 cd A and 63.8 lm W, respectively. In comparison, devices with SMPI-TPA (30 nm):5 wt% Ir(ppy) exhibit high and values of 65.2 cd A and 67.1 lm W, respectively. Maximum values of 19.6% and 23.4% were obtained from SMPI-TPA:Ir(ppy) and SMPI-Cz:Ir(ppy), respectively. These device performances indicate that the phenanthroimidazole unit is a tunable building unit for efficient carrier injection and it may also be employed as a host for green OLEDs.
对（）-4'-(1-(4-(2-(1-(4-吗啉基苯基)-1-菲并[9,10-]咪唑-2-基)乙烯基)phenyl)-1-菲并[9,10-]咪唑-2-基)-,-二苯基-[1,1'-联苯]-4-胺（SMPI-TPA）和（）-4-(4-(2-(4-(2-(4-(9-咔唑-9-基)phenyl)-1-菲并[9,10-]咪唑-1-基)苯乙烯基)-1-菲并[9,10-]咪唑-1-基)phenyl)吗啉（SMPI-Cz）进行了比较光学、电致发光和理论研究。这些化合物表现出优异的热性能、双电荷传输性能，并在热蒸发下形成薄膜。基于SMPI-TPA的蓝色有机发光二极管（CIE：0.16，0.08）在低开启电压下显示出高效的器件性能（6.1%；5.3 cd A；5.2 lm W）。SMPI-TPA和SMPI-Cz均被用作绿色有机发光二极管的主体材料。含有SMPI-Cz（30 nm）：5 wt% Ir(ppy)的器件表现出最大亮度为20725 cd m，电流效率和功率效率值分别为61.4 cd A和63.8 lm W。相比之下，含有SMPI-TPA（30 nm）：5 wt% Ir(ppy)的器件电流效率和功率效率值分别高达65.2 cd A和67.1 lm W。SMPI-TPA:Ir(ppy)和SMPI-Cz:Ir(ppy)的最大外量子效率值分别为19.6%和23.4%。这些器件性能表明菲并咪唑单元是用于高效载流子注入的可调节构建单元，并且它也可被用作绿色有机发光二极管的主体材料。
