Diphenylphosphorylpyridine-functionalized iridium complexes for high-efficiency monochromic and white organic light-emitting diodes
作者:Lijun Deng、Ting Zhang、Renjie Wang、Jiuyan Li
DOI:10.1039/c2jm32811a
日期:——
Four new cyclometalated iridium(III) complexes containing 2-aryl-5-diphenylphosphorylpyridine ligands, in which the aryl was difluorophenyl (Ir-1), phenyl (Ir-2), 4-(diphenylamino)phenyl (Ir-3) and 2-naphthyl (Ir-4), have been synthesized for application in organic light-emitting diodes (OLEDs). The incorporation of diphenylphosphoryl on the pyridine causes a decrease of the lowest unoccupied molecular orbital (LUMO) for the iridium complexes and the universal bathochromic shift by as much as 50 nm in their phosphorescence. In particular, the presence of the diphenylphosphoryl group on the 2-difluorophenylpyridine ligand of iridium(III)bis(4,6-(difluorophenyl)pyridinato-N,C2′)picolinate (FIrpic) redistributed the LUMO from the ancillary ligand entirely to the cyclometalating ligand. These complexes were used as doped emitters to fabricate OLEDs. The bluish-green device based on Ir-1 exhibited a maximum luminance efficiency of 43.6 cd A−1 (22.8 lm W−1, 9.5%). Highly efficient yellow devices were obtained with 51.6 cd A−1 (27 lm W−1, 14.5%) and 29.6 cd A−1 (15.5 lm W−1, 8.8%) for Ir-2 and Ir-3, respectively. The maximum luminance efficiency of 27.2 cd A−1 (15.5 lm W−1, 9.7%) was achieved for the orange-red device containing Ir-4. Furthermore, a two-emitting-component white OLED was fabricated with Ir-4 in combination with the traditional sky-blue FIrpic and a high efficiency of 23.9 cd A−1 (13.9 lm W−1, 5.4%) with CIE (0.29, 0.43) was realized.
我们合成了四种含有 2-芳基-5-二苯基膦酰基吡啶配体的新型环甲基化铱(III)配合物,其中芳基为二氟苯基(Ir-1)、苯基(Ir-2)、4-(二苯基氨基)苯基(Ir-3)和 2-萘基(Ir-4),这些配合物可应用于有机发光二极管(OLED)。在吡啶上加入二苯基磷酰会导致铱复合物的最低未占分子轨道(LUMO)减小,并使其磷光发生普遍的浴色偏移,偏移量高达 50 nm。特别是,双(4,6-(二氟苯基)吡啶-N,C2′)吡啶甲酸铱(III)(FIrpic)的 2-二氟苯基吡啶配体上二苯基磷酰基的存在使 LUMO 从辅助配体完全重新分配到环化配体上。这些配合物被用作掺杂发光体来制造有机发光二极管。基于 Ir-1 的蓝绿色器件的最大发光效率为 43.6 cd A-1(22.8 lm W-1,9.5%)。Ir-2 和 Ir-3 分别获得了 51.6 cd A-1(27 lm W-1,14.5%)和 29.6 cd A-1(15.5 lm W-1,8.8%)的高效黄色器件。含有 Ir-4 的橙红色装置的最大光效为 27.2 cd A-1 (15.5 lm W-1, 9.7%)。此外,还利用 Ir-4 与传统的天蓝色 FIrpic 结合制造出了双发光成分的白色 OLED,并实现了 23.9 cd A-1 (13.9 lm W-1,5.4%)的高效率,CIE 值为 0.29,0.43。