An oligocarbazole-encapsulated heteroleptic red iridium complex for solution-processed nondoped phosphorescent organic light-emitting diodes with over 10% external quantum efficiency
An oligocarbazole-encapsulated heteroleptic red iridium complex for solution-processed nondoped phosphorescent organic light-emitting diodes with over 10% external quantum efficiency
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An%20低聚咔唑封装%20杂配%20红色%20铱%20络合物%20for%20溶液处理%20非掺杂%20磷光%20有机%20发光%20二极管%20with%20over%2010%%20外部%20量子%20效率
DOI：
10.1039/c7tc00145b
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发表时间：
2017-06-21
影响因子：
6.4
通讯作者：
Wang, Lixiang
中科院分区：
文献类型：
--
作者：
Chen, Lingcheng;Wang, Shumeng;Wang, Lixiang
通过在有机电致发光器件（PhOLED）的CN和OO配体上分别包封低聚咔唑（oligocarbazole），合成了一种新型的自主体红色Ir树枝状化合物D-（PPQ）（2）Ir（acac）.由于树枝状楔的屏蔽作用，（PPQ）（2）Ir（acac）到D-（PPQ）（2）Ir（acac）的分子间相互作用和发光猝灭显著降低。相应地，混合溶液处理的电致磷光器件的最大外量子效率（EQE）从0.5%增加到9.9%。此外，D-（PPQ）（2）Ir（acac）在大尺寸咔唑树枝化基元的存在下表现出良好的耐醇性。这样的特征确实有利于通过正交溶剂处理成功地制造全溶液处理的器件，揭示了优化的EQE高达11.1%（8.7 cd A（-1），6.0 lm W-1），CIE坐标为（0.67，0.33）。结果表明，高效率的溶液处理的红色发光的非掺杂的PhOLED与超过10%的EQE也可以实现基于自主体磷光树枝状大分子系统。
A novel self-host red Ir dendrimer D-(PPQ)(2)Ir(acac) has been developed for solution-processed nondoped phosphorescent organic light-emitting diodes (PhOLEDs) by fully encapsulating the heteroleptic complex (PPQ)(2)Ir(acac) with oligocarbazole at both the CN and OO ligands. Due to the shielding effect of the dendritic wedge, the intermolecular interactions and luminescence quenching are found to be significantly reduced from (PPQ)(2)Ir(acac) to D-(PPQ)(2)Ir(acac). Correspondingly, the maximum external quantum efficiency (EQE) of hybrid-solution-processed electrophosphorescent devices is increased from 0.5% to 9.9%. Moreover, D-(PPQ)(2)Ir(acac) shows a good alcohol resistance in the presence of the large-size carbazole dendrons. Such a feature does favor the successful fabrication of all-solution-processed devices via an orthogonal solvent processing, revealing an optimized EQE as high as 11.1% (8.7 cd A(-1), 6.0 lm W-1) with CIE coordinates of (0.67, 0.33). The results indicate that highly efficient solution-processed red-emitting nondoped PhOLEDs with over 10% EQE can also be realized based on a self-host phosphorescent dendrimer system.