Binaphthyl-Containing Green- and Red-Emitting Molecules for Solution-Processable Organic Light-Emitting Diodes

Authors

  • Yi Zhou,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
    2. Graduate University of the Chinese Academy of Sciences Beijing, 100039 (PR China)
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  • Qingguo He,

    Corresponding author
    1. Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai, 200050 (PR China)
    • Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai, 200050 (PR China).
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  • Yi Yang,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
    2. Graduate University of the Chinese Academy of Sciences Beijing, 100039 (PR China)
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  • Haizheng Zhong,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
    2. Graduate University of the Chinese Academy of Sciences Beijing, 100039 (PR China)
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  • Chang He,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
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  • Guangyi Sang,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
    2. Graduate University of the Chinese Academy of Sciences Beijing, 100039 (PR China)
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  • Wei Liu,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
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  • Chunhe Yang,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
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  • Fenglian Bai,

    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
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  • Yongfang Li

    Corresponding author
    1. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China)
    • Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry, Chinese Academy of Sciences Beijing, 100190 (PR China).
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  • This work was supported by the NSFC (Nos. 50633050, 20721061, 50503020, and 20773156).

Abstract

Strong intermolecular interactions usually result in decreases in solubility and fluorescence efficiency of organic molecules. Therefore, amorphous materials are highly pursued when designing solution-processable, electroluminescent organic molecules. In this paper, a non-planar binaphthyl moiety is presented as a way of reducing intermolecular interactions and four binaphthyl-containing molecules (BNCMs): green-emitting BBB and TBT as well as red-emitting BTBTB and TBBBT, are designed and synthesized. The photophysical and electrochemical properties of the molecules are systematically investigated and it is found that TBT, TBBBT, and BTBTB solutions show high photoluminescence (PL) quantum efficiencies of 0.41, 0.54, and 0.48, respectively. Based on the good solubility and amorphous film-forming ability of the synthesized BNCMs, double-layer structured organic light-emitting diodes (OLEDs) with BNCMs as emitting layer and poly(N-vinylcarbazole) (PVK) or a blend of poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] and PVK as hole-transporting layer are fabricated by a simple solution spin-coating procedure. Amongst those, the BTBTB based OLED, for example, reaches a high maximum luminance of 8315 cd · m−2 and a maximum luminous efficiency of 1.95 cd · A−1 at a low turn-on voltage of 2.2 V. This is one of the best performances of a spin-coated OLED reported so far. In addition, by doping the green and red BNCMs into a blue-emitting host material poly(9,9-dioctylfluorene-2,7-diyl) high performance white light-emitting diodes with pure white light emission and a maximum luminance of 4000 cd · m−2 are realized.

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