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Energy Express

Energy Express

  • Editor: Christian Seassal
  • Vol. 20, Iss. S6 — Nov. 5, 2012
  • pp: A932–A940

White organic light emitting diodes with enhanced internal and external outcoupling for ultra-efficient light extraction and Lambertian emission

Tobias Bocksrocker, Jan Benedikt Preinfalk, Julian Asche-Tauscher, Andreas Pargner, Carsten Eschenbaum, Florian Maier-Flaig, and Uli Lemme  »View Author Affiliations

Optics Express, Vol. 20, Issue S6, pp. A932-A940 (2012)

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White organic light emitting diodes (WOLEDs) suffer from poor outcoupling efficiencies. The use of Bragg-gratings to enhance the outcoupling efficiency is very promising for light extraction in OLEDs, but such periodic structures can lead to angular or spectral dependencies in the devices. Here we present a method which combines highly efficient outcoupling by a TiO2-Bragg-grating leading to a 104% efficiency enhancement and an additional high quality microlens diffusor at the substrate/air interface. With the addition of this diffusor, we achieved not only a uniform white emission, but also further increased the already improved device efficiency by another 94% leading to an overall enhancement factor of about 4.

© 2012 OSA

OCIS Codes
(050.1950) Diffraction and gratings : Diffraction gratings
(230.3670) Optical devices : Light-emitting diodes
(230.7390) Optical devices : Waveguides, planar
(250.3680) Optoelectronics : Light-emitting polymers

ToC Category:
Light-Emitting Diodes

Original Manuscript: August 17, 2012
Revised Manuscript: September 21, 2012
Manuscript Accepted: October 9, 2012
Published: October 15, 2012

Tobias Bocksrocker, Jan Benedikt Preinfalk, Julian Asche-Tauscher, Andreas Pargner, Carsten Eschenbaum, Florian Maier-Flaig, and Uli Lemme, "White organic light emitting diodes with enhanced internal and external outcoupling for ultra-efficient light extraction and Lambertian emission," Opt. Express 20, A932-A940 (2012)

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