The Influence of Quasiplanar Structures of Partially Oxygen-Bridged Triphenylamine Dimers on the Properties of Their Bulk Films

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Abstract

The relationship between molecular orientation and charge-transporting properties in vapor-deposited films of two doubly oxygen-bridged triphenylamine dimers, which differ in their connection mode, was examined. A comparison of the fluorescence spectra obtained from these films, as well as from solution and the crystalline state revealed that the dimers retain two different states in amorphous films, i.e., a monomer-like random orientation and a crystalline-like π-stacking orientation. Regarding the crystalline-like π-stacking orientation in the films, one dimer forms a one-dimensional π-stacking structure, whereas the other dimer forms a two-dimensional π-stacking structure, thus reflecting the difference in packing structure in the crystals. Time-of-flight measurements showed a strong dependence of the charge mobilities in the film of the dimer with a one-dimensional π-stacking structure on the electric field. The film of the dimer with a two-dimensional π-stacking structure exhibited ambipolar charge-transport properties with high electron and hole mobilities. When these dimers were used as hole injection layers in organic light-emitting diode devices, the external quantum efficiencies improved by a factor of 1.2 relative to standard devices.

Journal

  • Bulletin of the Chemical Society of Japan

    Bulletin of the Chemical Society of Japan 89(6), 726-732, 2016

    The Chemical Society of Japan

Codes

  • NII Article ID (NAID)
    130005157273
  • NII NACSIS-CAT ID (NCID)
    AA00580132
  • Text Lang
    ENG
  • ISSN
    0009-2673
  • NDL Article ID
    027425009
  • NDL Call No.
    Z53-B35
  • Data Source
    NDL  J-STAGE 
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