Highly Efficient Green-Emitting Phosphorescent Iridium Dendrimers Based on Carbazole Dendrons

Authors

  • J. Ding,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • J. Gao,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • Y. Cheng,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • Z. Xie,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • L. Wang,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • D. Ma,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • X. Jing,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • F. Wang

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P.R. China
    2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • This work was supported by the National Natural Science Foundation of China (Nos. 29725410 and 29992530) and 973 Project (2002CB613401).

Abstract

Green-emitting iridium dendrimers with rigid hole-transporting carbazole dendrons are designed, synthesized, and investigated. With second-generation dendrons, the photoluminescence quantum yield of the dendrimers is up to 87 % in solution and 45 % in a film. High-quality films of the dendrimers are fabricated by spin-coating, producing highly efficient, non-doped electrophosphorescent organic light-emitting diodes (OLEDs). With a device structure of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)/neat dendrimer/1,3,5-tris(2-N-phenylbenzimidazolyl)benzene/LiF/Al, a maximum external quantum efficiency (EQE) of 10.3 % and a maximum luminous efficiency of 34.7 cd A–1 are realized. By doping the dendrimers into a carbazole-based host, the maximum EQE can be further increased to 16.6 %. The integration of rigid hole-transporting dendrons and phosphorescent complexes provides a new route to design highly efficient solution-processable dendrimers for OLED applications.

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