Jump to main content
Jump to site search


Increasing the horizontal orientation of transition dipole moments in solution processed small molecular emitters

Author affiliations

Abstract

The efficiency of organic light emitting diodes (OLEDs) can be improved by controlling the orientation of the transition dipole moment of the emitters. Currently, no effective methods exist for orienting the transition dipole moments in solution processed active layers for OLEDs. We investigate the orientation of the transition dipole moment of small molecular emitters in a host matrix of poly(9,9-dioctylfluorene) (PFO) by means of angle dependent luminescence intensity measurements. The polymer chains of the host orient predominantly in the plane of the film. Fluorescent p-phenylenevinylene oligomers with 6 and 7 repeat units (OPV6, OPV7) are found to also orient preferentially horizontally. The orientation of the emitters can be improved by thermal annealing with up to 90% of transition dipole moments oriented in the plane of the film. The phosphorescent emitter Ir(MDQ)2(acac) shows a degree of horizontal orientation in the polymeric host matrix lower than that which is observed for oligomers, but as high as is observed for the same emitter in evaporated layers. A carbazole derivative capable of thermally activated delayed fluorescence shows a small preference for vertical orientation within the polymer host. The strong orientation of OPV6 and OPV7 in the oriented polymer host is rationalized in terms of their high aspect ratios. The use of PFO as host material in host/guest systems allows achieving horizontal orientation of transition dipole moments in solution processed oligomers and small molecular emitters.

Graphical abstract: Increasing the horizontal orientation of transition dipole moments in solution processed small molecular emitters

Back to tab navigation

Supplementary files

Publication details

The article was received on 11 Apr 2017, accepted on 12 Jun 2017 and first published on 12 Jun 2017


Article type: Paper
DOI: 10.1039/C7TC01568B
Citation: J. Mater. Chem. C, 2017, Advance Article
  • Open access: Creative Commons BY license
  •   Request permissions

    Increasing the horizontal orientation of transition dipole moments in solution processed small molecular emitters

    A. Senes, S. C. J. Meskers, H. Greiner, K. Suzuki, H. Kaji, C. Adachi, J. S. Wilson and R. A. J. Janssen, J. Mater. Chem. C, 2017, Advance Article , DOI: 10.1039/C7TC01568B

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements