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Energy Express

Energy Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. S6 — Nov. 7, 2011
  • pp: A1272–A1280

Optics InfoBase > Energy Express > Volume 19 > Issue S6 > Page A1272

Microporous phase-separated films of polymer blends for enhanced outcoupling of light from OLEDs

Rui Liu, Zhuo Ye, Joong-Mok Park, Min Cai, Ying Chen, Kai-Ming Ho, Ruth Shinar, and Joseph Shinar  »View Author Affiliations


Optics Express, Vol. 19, Issue S6, pp. A1272-A1280 (2011)
http://dx.doi.org/10.1364/OE.19.0A1272


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Abstract

Thin microporous films were formed by dropcasting a toluene solution containing various ratios of polystyrene:polyethylene glycol blends on a glass substrate, with OLEDs on the ITO that coated the opposite side of that substrate. We demonstrate for the first time that such easily-fabricated films with surface and bulk micropores in the index-matching polystyrene can serve as random microlens-like arrays to improve forward OLED light extraction by up to ~60%. A theoretical interpretation of the angular emission profile of the device, considering the geometrical change at the substrate/air interface and the scattering by the pores within the films, was established in excellent agreement with the experiments. The use of such blended thin films provides an economical method, independent of the OLED fabrication technique, for improving the outcoupling efficiency.

© 2011 OSA

OCIS Codes
(080.3630) Geometric optics : Lenses
(230.3990) Optical devices : Micro-optical devices

ToC Category:
Light-Emitting Diodes

History
Original Manuscript: August 15, 2011
Revised Manuscript: October 6, 2011
Manuscript Accepted: October 7, 2011
Published: November 7, 2011

Virtual Issues
Organic Light-Emitting Diodes (2011) Optics Express
November 11, 2011 Spotlight on Optics

Citation
Rui Liu, Zhuo Ye, Joong-Mok Park, Min Cai, Ying Chen, Kai-Ming Ho, Ruth Shinar, and Joseph Shinar, "Microporous phase-separated films of polymer blends for enhanced outcoupling of light from OLEDs," Opt. Express 19, A1272-A1280 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-S6-A1272


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References

  1. S. R. Forrest, “The path to ubiquitous and low-cost organic electronic appliances on plastic,” Nature428(6986), 911–918 (2004). [CrossRef] [PubMed]
  2. Organic Electronics: Materials, Processing, Devices and Applications, F. So, ed. (CRC, 2010)
  3. Organic Electronics in Sensors and Biotechnology, R. Shinar and J. Shinar, eds., (McGraw-Hill, 2009)
  4. J. Shinar and R. Shinar, “Organic light-emitting devices (OLEDs) and OLED-based chemical and biological sensors: an overview,” J. Phys. D Appl. Phys.41(13), 133001 (2008). [CrossRef]
  5. Y. Sun and S. R. Forrest, “Enhanced light out-coupling of organic light-emitting devices using embedded low-index grids,” Nat. Photonics2(8), 483–487 (2008). [CrossRef]
  6. J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12(5), 809–817 (2011). [CrossRef]
  7. M. Slootsky and S. R. Forrest, “Enhancing waveguided light extraction in organic LEDs using an ultra-low-index grid,” Opt. Lett.35(7), 1052–1054 (2010). [CrossRef] [PubMed]
  8. W. H. Koo, S. M. Jeong, F. Araoka, K. Ishikawa, S. Nishimura, T. Toyooka, and H. Takezoe, “Light extraction from organic light-emitting diodes enhanced by spontaneously formed buckles,” Nat. Photonics4(4), 222–226 (2010). [CrossRef]
  9. A. O. Altun, S. Jeon, J. Shim, J.-H. Jeong, D.-G. Choi, K.-D. Kim, J.-H. Choi, S.-W. Lee, E.-S. Lee, H.-D. Park, J. R. Youn, J.-J. Kim, Y.-H. Lee, and J.-W. Kang, “Corrugated organic light emitting diodes for enhanced light extraction,” Org. Electron.11(5), 711–716 (2010). [CrossRef]
  10. H. J. Peng, Y. L. Ho, X. J. Yu, and H. S. Kwok, “Enhanced coupling of light from organic light emitting diodes using nanoporous films,” J. Appl. Phys.96(3), 1649–1654 (2004). [CrossRef]
  11. S. Mladenovski, K. Neyts, D. Pavicic, A. Werner, and C. Rothe, “Exceptionally efficient organic light emitting devices using high refractive index substrates,” Opt. Express17(9), 7562–7570 (2009). [CrossRef] [PubMed]
  12. B. W. D’Andrade and J. J. Brown, “Organic light-emitting device luminaire for illumination applications,” Appl. Phys. Lett.88(19), 192908 (2006). [CrossRef]
  13. L. Lu, F. Zhang, Z. Xu, S. Zhao, Z. Zhuo, D. Song, J. Li, and Y. Wang, “Characteristics of ZnS nanocolumn arrays and their effect on the light outcoupling of OLEDs,” Physica B405(17), 3728–3731 (2010). [CrossRef]
  14. S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature459(7244), 234–238 (2009). [CrossRef] [PubMed]
  15. J.-M. Park, Z. Gan, W. Y. Leung, R. Liu, Z. Ye, K. Constant, J. Shinar, R. Shinar, and K.-M. Ho, “Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction,” Opt. Express19(S4Suppl 4), A786–A792 (2011). [CrossRef] [PubMed]
  16. Y. Sun and S. R. Forrest, “Organic light emitting devices with enhanced outcoupling via microlenses fabricated by imprint lithography,” J. Appl. Phys.100(7), 073106 (2006). [CrossRef]
  17. J. Lim, S. S. Oh, D. Y. Kim, S. H. Cho, I. T. Kim, S. H. Han, H. Takezoe, E. H. Choi, G. S. Cho, Y. H. Seo, S. O. Kang, and B. Park, “Enhanced out-coupling factor of microcavity organic light-emitting devices with irregular microlens array,” Opt. Express14(14), 6564–6571 (2006). [CrossRef] [PubMed]
  18. H. Y. Lin, Y. H. Ho, J. H. Lee, K. Y. Chen, J. H. Fang, S. C. Hsu, M. K. Wei, H. Y. Lin, J. H. Tsai, and T. C. Wu, “Patterned microlens array for efficiency improvement of small-pixelated organic light-emitting devices,” Opt. Express16(15), 11044–11051 (2008). [CrossRef] [PubMed]
  19. S.-H. Eom, E. Wrzesniewski, and J. Xue, “Close-packed hemispherical microlens arrays for light extraction enhancement in organic light-emitting devices,” Org. Electron.12(3), 472–476 (2011). [CrossRef]
  20. W.-K. Huang, W.-S. Wang, H.-C. Kan, and F.-C. Chen, “Enhanced light out-coupling efficiency of organic light-emitting diodes with self-organized microlens arrays,” Jpn. J. Appl. Phys.45(41), L1100–L1102 (2006). [CrossRef]
  21. J. A. Zimberlin, P. Wadsworth, and A. J. Crosby, “Living microlens arrays,” Cell Motil. Cytoskeleton65(9), 762–767 (2008). [CrossRef] [PubMed]
  22. P. Ruffieux, T. Scharf, I. Philipoussis, H. P. Herzig, R. Voelkel, and K. J. Weible, “Two step process for the fabrication of diffraction limited concave microlens arrays,” Opt. Express16(24), 19541–19549 (2008). [CrossRef] [PubMed]
  23. J. S. Kim, D. S. Kim, J. J. Kang, J. D. Kim, and C. J. Hwang, “Replication and comparison of concave and convex microlens arrays of light guide plate for liquid crystal display in injection molding,” Polym. Eng. Sci.50(8), 1696–1704 (2010). [CrossRef]
  24. S. Walheim, M. Böltau, J. Mlynek, G. Krausch, and U. Steiner, “Structure formation via polymer demixing in spin-cast films,” Macromolecules30(17), 4995–5003 (1997). [CrossRef]
  25. J. E. G. J. Wijnhoven and W. L. Vos, “Preparation of photonic crystals made of air spheres in titania,” Science281(5378), 802–804 (1998). [CrossRef] [PubMed]
  26. M. Ulbricht, “Advanced functional polymer membranes,” Polymer (Guildf.)47(7), 2217–2262 (2006). [CrossRef]
  27. G. K. Stylios, P. V. Giannoudis, and T. Wan, “Applications of nanotechnologies in medical practice,” Injury36(4Suppl 4), S6–S13 (2005). [CrossRef] [PubMed]
  28. J.-K. Kim, K. Taki, and M. Ohshima, “Preparation of a unique microporous structure via two step phase separation in the course of drying a ternary polymer solution,” Langmuir23(24), 12397–12405 (2007). [CrossRef] [PubMed]
  29. J.-K. Kim, K. Taki, S. Nagamine, and M. Ohshima, “Periodic porous stripe patterning in a polymer blend film induced by phase separation during spin-casting,” Langmuir24(16), 8898–8903 (2008). [CrossRef] [PubMed]
  30. K.-H. Wu, S.-Y. Lu, and H.-L. Chen, “Formation of parallel strips in thin films of polystyrene/poly(vinyl pyrrolidone) blends via spin coating on unpatterned substrates,” Langmuir22(19), 8029–8035 (2006). [CrossRef] [PubMed]
  31. C. F. Madigan, M.-H. Lu, and J. C. Sturm, “Improvement of output coupling efficiency of organic light-emitting diodes by backside substrate modification,” Appl. Phys. Lett.76(13), 1650–1652 (2000). [CrossRef]
  32. M. Cai, T. Xiao, R. Liu, Y. Chen, R. Shinar, and J. Shinar, “Indium tin oxide-free tris(8-hydroxyquinoline) Al OLEDs with 80% enhanced power efficiency,” Appl. Phys. Lett. (in press).

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