Shin Hyun, Ha Yeon Hee, Kim Hyun-Gu, Kim Ran, Kwon Soon-Ki, Kim Yun-Hi, Kim Jang-Joo
Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea.
Department of Chemistry and RIGET, Gyeongsang National University, Jinju, 52828, South Korea.
Adv Mater. 2019 May;31(21):e1808102. doi: 10.1002/adma.201808102. Epub 2019 Apr 10.
Deep-blue emitting Iridium (Ir) complexes with horizontally oriented emitting dipoles are newly designed and synthesized through engineering of the ancillary ligand, where 2',6'-difluoro-4-(trimethylsilyl)-2,3'-bipyridine (dfpysipy) is used as the main ligand. Introduction of a trimethylsilyl group at the pyridine and a nitrogen at the difluoropyrido group increases the bandgap of the emitter, resulting in deep-blue emission. Addition of a methyl group (mpic) to a picolinate (pic) ancillary ligand or replacement of an acetate structure of pic with a perfluoromethyl-triazole structure (fptz) increases the horizontal component of the emitting dipoles in sequence of mpic (86%) > fptz (77%) > pic (74%). The organic light-emitting diode (OLED) using the Ir complex with the mpic ancillary ligand shows the highest external quantum efficiency (31.9%) among the reported blue OLEDs with a y-coordinate value lower than 0.2 in the 1931 Commission Internationale de L'Eclairage (CIE) chromaticity diagram.
通过辅助配体工程新设计并合成了具有水平取向发射偶极子的深蓝色发光铱（Ir）配合物，其中2'，6'-二氟-4-（三甲基甲硅烷基）-2，3'-联吡啶（dfpysipy）用作主要配体。在吡啶处引入三甲基甲硅烷基和在二氟吡啶基处引入氮会增加发射体的带隙，从而产生深蓝色发射。向吡啶甲酸（pic）辅助配体中添加甲基（mpic）或将pic的乙酸酯结构替换为全氟甲基三唑结构（fptz）会按mpic（86%）>fptz（77%）>pic（74%）的顺序增加发射偶极子的水平分量。使用具有mpic辅助配体的Ir配合物的有机发光二极管（OLED）在1931国际照明委员会（CIE）色度图中y坐标值低于0.2的已报道蓝色OLED中显示出最高的外量子效率（31.9%）。
