Red-light-emitting iridium complexes with hole-transporting 9-arylcarbazole moieties for electrophosphorescence efficiency/color purity trade-off optimizationE
Red-light-emitting iridium complexes with hole-transporting 9-arylcarbazole moieties for electrophosphorescence efficiency/color purity trade-off optimizationE
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DOI：
10.1002/adfm.200700665
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发表时间：
2008-01-24
影响因子：
19
通讯作者：
Lin, Zhenyang
中科院分区：
文献类型：
--
作者：
Ho, Cheuk-Lam;Wong, Wai-Yeung;Lin, Zhenyang
报道了一种新的含9-芳基咔唑基发色团的环化异喹啉铱（III）红色磷光配合物的合成、结构、物理、电化学和电致磷光性质。这些红色荧光粉的功能特性与密度泛函理论计算的结果相关。这些配合物的最高占据分子轨道水平的提高，通过整合的咔唑单元的铱异喹啉核心，使空穴传输能力得到改善，在所得的配合物相对于那些与I-苯基异喹啉配体。所有的配合物都是高度热稳定的，并且在室温下发射强烈的红光，具有相对短的寿命，这对于高效的有机发光二极管（OLED）是有益的。使用这些染料作为磷光掺杂剂作为真空蒸发和旋涂的发光层制造的饱和红色OLED已经以多层结构实现，在国际照明委员会（CIE）坐标为（0.67，0.33）至（0.68，0.32）处具有出色的红色纯度。一些器件可以显示出非常高的效率，最大外部量子效率高达12%光子/电子。这些红色发光体的优异性能表明配体框架中咔唑模块的优势;通过改善空穴传输能力，促进激子传输来证明。因此，这些材料可以提供一个新的途径，合理设计的重金属电致磷光体，揭示了一个上级设备效率/色纯度的权衡所需的纯红光产生。
The synthesis, structures, photophysics, electrochemistry and electrophosphorescent properties of new red phosphorescent cyclometalated iridium(III) isoquinoline complexes, bearing 9-arylcarbazolyl chromophores, are reported. The functional properties of these red phosphors correlate well with the results of density functional theory calculations. The highest occupied molecular orbital levels of these complexes are raised by the integration of a carbazole unit to the iridium isoquinoline core so that the hole-transporting ability is improved in the resulting complexes relative to those with I-phenylisoquinoline ligands. All of the complexes are highly thermally stable and emit an intense red light at room temperature with relatively short lifetimes that are beneficial for highly efficient organic light-emitting diodes (OLEDs). Saturated red OLEDs, fabricated using these dyes as the phosphorescent dopants both as vacuum-evaporated and spin-coated emissive layers, have been achieved in a multi-layer configuration with outstanding red color purity at Commission International de L'Eclairage (CIE) coordinates of (0.67,0.33) to (0.68,0.32). Some of the devices can show very high efficiencies with a maximum external quantum efficiency of up to 12 % photons per electron. The excellent performance of these red emitters indicates the advantage of the carbazole module in the ligand framework; demonstrated by an improved hole-transporting ability that facilitates exciton transport. These materials could thus provide a new avenue for the rational design of heavy-metal electrophosphors that reveal a superior device efficiency/color purity trade-off necessary for pure red-light generation.