Spectrally narrowed edge emission from leaky waveguide modes in OLEDs

Z. Q. Gan, Y. Tian, D. W. Lynch, Ji Hun Kang, Q. Han Park, J. Shinar

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A dramatic spectral line narrowing of the edge-emission, at room temperature, from tris(quinolinolate) Al (Alq3), N,N'-diphenyl-N,N'- bis(1-naphthylphenyl)-1,1 '-biphenyl-4,4'-diamine (NPD), 4,4'-bis(2,2'-diphenyl- vinyl)-1,1'-biphenyl (DPVBi), and some guest-host small molecular OLEDs, fabricated on ITO-coated glass, is described. In all but the DPVBi OLEDs, the narrowed emission band emerges above a threshold thickness of the emitting layer, and narrows down to a full width at half maximum of only 5-10 nm. The results demonstrate that this narrowed emission is due to irregular waveguide modes that leak from the ITO to the glass substrate at a grazing angle. While measurements of variable stripe length (l) devices exhibit an apparent weak optical gain, there is no observable threshold current or bias associated with this spectral narrowing. It is suspected that the apparent weak optical gain is due to misalignment of the axis of the waveguided mode and the axis of the collection lens of the probe, but it is not clear if such a misalignment can account for the for the observed evolution of the edge emission spectra with l.

Original languageEnglish
Title of host publicationOrganic Light Emitting Materials and Devices XI
Publication statusPublished - 2007
EventOrganic Light Emitting Materials and Devices XI - San Diego, CA, United States
Duration: 2007 Aug 262007 Aug 29

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOrganic Light Emitting Materials and Devices XI
Country/TerritoryUnited States
CitySan Diego, CA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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