Get access

An Alternative Approach to Constructing Solution Processable Multifunctional Materials: Their Structure, Properties, and Application in High-Performance Organic Light-Emitting Diodes

Authors

  • Shanghui Ye,

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    2. Graduate School, Chinese Academy of Science, Beijing 100039 (P. R. China)
    Search for more papers by this author
  • Yunqi Liu,

    Corresponding author
    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    2. Graduate School, Chinese Academy of Science, Beijing 100039 (P. R. China)
    • Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China).
    Search for more papers by this author
  • Kun Lu,

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    Search for more papers by this author
  • Weiping Wu,

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    Search for more papers by this author
  • Chunyan Du,

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    2. Graduate School, Chinese Academy of Science, Beijing 100039 (P. R. China)
    Search for more papers by this author
  • Ying Liu,

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    2. Graduate School, Chinese Academy of Science, Beijing 100039 (P. R. China)
    Search for more papers by this author
  • Hongtao Liu,

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    Search for more papers by this author
  • Ti Wu,

    1. Graduate School, Chinese Academy of Science, Beijing 100039 (P. R. China)
    Search for more papers by this author
  • Gui Yu

    1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P. R. China)
    Search for more papers by this author

Abstract

A new series of full hydrocarbons, namely 4,4′-(9,9′-(1,3-phenylene)bis(9H-fluorene-9,9-diyl))bis(N,N-diphenylaniline) (DTPAFB), N,N′-(4,4′-(9,9′-(1,3-phenylene)bis(9H-fluorene-9,9-diyl))bis(4,1-phenylene))bis(N-phenylnaphthalen-1-amine) (DNPAFB), 1,3-bis(9-(4-(9H-carbazol-9-yl)phenyl)-9H-fluoren-9-yl)benzene, and 1,3-bis(9-(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)-9H-fluoren-9-yl)benzene, featuring a highly twisted tetrahedral conformation, are designed and synthesized. Organic light-emitting diodes (OLEDs) comprising DNPAFB and DTPAFB as hole transporting layers and tris(quinolin-8-yloxy)aluminum as an emitter are made either by vacuum deposition or by solution processing, and show much higher maximum efficiencies than the commonly used N,N′-di(naphthalen-1-yl)-N,N′-diphenylbiphenyl-4,4′-diamine device (3.6 cd A−1) of 7.0 cd A−1 and 6.9 cd A−1, respectively. In addition, the solution processed blue phosphorescent OLEDs employing the synthesized materials as hosts and iridium (III) bis[(4,6-di-fluorophenyl)-pyridinato-N, C2] picolinate (FIrpic) phosphor as an emitter present exciting results. For example, the DTPAFB device exhibits a brightness of 47 902 cd m−2, a maximum luminescent efficiency of 24.3 cd A−1, and a power efficiency of 13.0 lm W−1. These results show that the devices are among the best solution processable blue phosphorescent OLEDs based on small molecules. Moreover, a new approach to constructing solution processable small molecules is proposed based on rigid and bulky fluorene and carbazole moieties combined in a highly twisted configuration, resulting in excellent solubility as well as chemical miscibility, without the need to introduce any solubilizing group such as an alkyl or alkoxy chain.

Ancillary