Solution-Processible Red Iridium Dendrimers based on Oligocarbazole Host Dendrons: Synthesis, Properties, and their Applications in Organic Light-Emitting Diodes

Authors

  • Junqiao Ding,

    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
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  • Jianhong Lü,

    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
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  • Yanxiang Cheng,

    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
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  • Zhiyuan Xie,

    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
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  • Lixiang Wang,

    Corresponding author
    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
    • State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China).
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  • Xiabin Jing,

    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
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  • Fosong Wang

    1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 (P. R. China)
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  • This work is supported by the National Natural Science Foundation of China (No.20474067, 50673088 and 50633040), Science Fund for Creative Research Groups (No.20621401), and 973 Project (2002CB613401).

Abstract

A series of novel red-emitting iridium dendrimers functionalized with oligocarbazole host dendrons up to the third generation (red-G3) have been synthesized by a convergent method, and their photophysical, electrochemical, and electroluminescent properties have been investigated. In addition to controlling the intermolecular interactions, oligocarbazole-based dendrons could also participate in the electrochemical and charge-transporting process. As a result, highly efficient electrophosphorescent devices can be fabricated by spin-coating from chlorobenzene solution in different device configurations. The maximum external quantum efficiency (EQE) based on the non-doped device configuration increases monotonically with increasing dendron generation. An EQE as high as 6.3% was obtained as for the third generation dendrimer red-G3, which is about 30 times higher than that of the prototype red-G0. Further optimization of the device configuration gave an EQE of 11.8% (13.0 cd A−1, 7.2 lm W−1) at 100 cd m−2 with CIE coordinates of (0.65, 0.35). The state-of-the-art performance indicated the potential of these oligocarbazole-based red iridium dendrimers as solution processible emissive materials for organic light-emitting diode applications.

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