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Simple Bipolar Hosts with High Glass Transition Temperatures Based on 1,8-Disubstituted Carbazole for Efficient Blue and Green Electrophosphorescent Devices with “Ideal” Turn-on Voltage

Authors

  • Dr. Hong Huang,

    1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
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  • Yixin Wang,

    1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
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  • Biao Pan,

    1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
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  • Xiao Yang,

    1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
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  • Prof. Dr. Lei Wang,

    Corresponding author
    1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
    • Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
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  • Dr. Jiangshan Chen,

    Corresponding author
    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022 (P. R. China)
    • State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022 (P. R. China)
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  • Prof. Dr. Dongge Ma,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022 (P. R. China)
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  • Prof. Dr. Chuluo Yang

    Corresponding author
    1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
    2. Department of Chemistry, Wuhan University, Wuhan 430072 (P. R. China)
    • Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (P. R. China)
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Abstract

Two hybrids based on 1,8-disubstituted carbazole, 1,8-OXDCz and 1,8-mBICz, have been designed and synthesized through a facile process. The incorporation of oxadiazole or N-phenylbenzimidazole moieties at the 1,8-positions of carbazole greatly improves its morphological stability, giving glass transition temperatures (Tg) as high as 138 and 154 °C, respectively. Blue phosphorescent organic light-emitting devices (PhOLEDs) with 1,8-mBICz exhibit almost the same performance as a similarly structured device based on the mCP host, and green PhOLEDs employing the new host material 1,8-OXDCz exhibit an ideal turn-on voltage (2.5 V at 1.58 cd m−2), a maximum current efficiency (ηc,max) of 73.9 cd A−1, and a power efficiency (ηp,max) of 89.7 lm W−1. These results are among the best performances of [Ir(ppy)3]-based devices with simple device configurations.

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