OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 22, Iss. 10 — May. 19, 2014
  • pp: 12392–12397

Enhancement of light extraction efficiency of OLEDs using Si3N4-based optical scattering layer

Sang-Jun Park, Yang Doo Kim, Ho Won Lee, Hyung Jin Yang, Joong-Yeon Cho, Young Kwan Kim, and Heon Lee  »View Author Affiliations


Optics Express, Vol. 22, Issue 10, pp. 12392-12397 (2014)
http://dx.doi.org/10.1364/OE.22.012392


View Full Text Article

Enhanced HTML    Acrobat PDF (1524 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

An optical scattering layer, consisting of a Si3N4 nano-pillar array and a spin-coated hydrogen silsesquioxane (HSQ) planarization layer, was introduced to an organic light-emitting diode (OLED) substrate to increase the out-coupling efficiency. After plasma enhanced chemical vapor deposition (PECVD) of the Si3N4 layer, the nano-pillar array was created using nanoimprint lithography and reactive ion etching. As the Si3N4 pillar array has a refractive index of 2.0, photons generated in the organic layer are scattered by the Si3N4 structures and thus have a higher chance of being emitted from the device. The spin-coated HSQ planarization layer produces a flat substrate, which is essential for depositing a uniform organic material layer and assuring the electric conductivity of the transparent conducting oxide (TCO) layer. In this study, Si3N4 nano-structures with a height of 100 or 300 nm were used to enhance the out-coupling efficiency of the OLED devices. Although the electrical conductivity of the TCO layer deposited on the light scattering layer was slightly degraded, the OLED devices formed with the light scattering layer exhibited a higher luminous power at given electrical power. Consequently, the use of a planarized 300-nm-thick Si3N4 layer increased the external quantum efficiency of the OLED device by 50% at 10,000 cd/m2 compared to the reference OLED device fabricated on a flat glass substrate.

© 2014 Optical Society of America

OCIS Codes
(230.0230) Optical devices : Optical devices
(230.3670) Optical devices : Light-emitting diodes
(230.4000) Optical devices : Microstructure fabrication

ToC Category:
Optoelectronics

History
Original Manuscript: March 18, 2014
Revised Manuscript: May 1, 2014
Manuscript Accepted: May 2, 2014
Published: May 14, 2014

Citation
Sang-Jun Park, Yang Doo Kim, Ho Won Lee, Hyung Jin Yang, Joong-Yeon Cho, Young Kwan Kim, and Heon Lee, "Enhancement of light extraction efficiency of OLEDs using Si3N4-based optical scattering layer," Opt. Express 22, 12392-12397 (2014)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-10-12392


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. N. C. Greenham, R. H. Friend, D. D. C. Bradley, “Angular dependence of the emission from a conjugated polymer light-emitting diode: implications for efficiency calculations,” Adv. Mater. 6(6), 491–494 (1994). [CrossRef]
  2. V. Bulović, V. B. Khalfin, G. Gu, P. E. Burrows, D. Z. Garbuzov, S. R. Forrest, “Weak microcavity effects in organic light-emitting devices,” Phys. Rev. B 58(7), 3730–3740 (1998). [CrossRef]
  3. J.-S. Kim, P. K. H. Ho, N. C. Greenham, R. H. Friend, “Electroluminescence emission pattern of organic light-emitting diodes: Implications for device efficiency calculations,” J. Appl. Phys. 88(2), 1073 (2000).
  4. A. Chutinan, K. Ishihara, T. Asano, M. Fujita, S. Noda, “Theoretical analysis on light-extraction efficiency of organic light-emitting diodes using FDTD and mode-expansion methods,” Org. Electron. 6(1), 3–9 (2005). [CrossRef]
  5. S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008). [CrossRef]
  6. R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010). [CrossRef]
  7. S.-Y. Kim, J.-J. Kim, “Outcoupling efficiency of organic light emitting diodes and the effect of ITO thickness,” Org. Electron. 11(6), 1010–1015 (2010). [CrossRef]
  8. I. Schnitzer, E. Yablonovitch, C. Caneau, T. J. Gmitter, A. Scherer, “30% external quantum efficiency from surface textured, thin‐film light‐emitting diodes,” Appl. Phys. Lett. 63(16), 2174–2176 (1993). [CrossRef]
  9. C. S. Choi, D.-Y. Kim, S.-M. Lee, M. S. Lim, K. C. Choi, H. Cho, T.-W. Koh, S. Yoo, “Blur-free outcoupling enhancement in transparent organic light emitting diodes: a nanostructure extracting surface plasmon modes,” Adv. Opt. Mater. 1(10), 687–691 (2013). [CrossRef]
  10. S. Möller, S. R. Forrest, “Improved light out-coupling in organic light emitting diodes employing ordered microlens arrays,” J. Appl. Phys. 91(5), 3324–3327 (2002). [CrossRef]
  11. J. Shakya, K. H. Kim, J. Y. Lin, H. X. Jiang, “Enhanced light extraction in III-nitride ultraviolet photonic crystal light-emitting diodes,” Appl. Phys. Lett. 85(1), 142–144 (2004). [CrossRef]
  12. J. J. Wierer, M. R. Krames, J. E. Epler, N. F. Gardner, M. G. Craford, J. R. Wendt, J. A. Simmons, M. M. Sigalas, “InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal structures,” Appl. Phys. Lett. 84(19), 3885 (2004). [CrossRef]
  13. Z. S. Zhang, B. Zhang, J. Xu, K. Xu, Z. J. Yang, Z. X. Qin, T. J. Yu, D. P. Yu, “Effects of symmetry of GaN-based two-dimensional photonic crystal with quasicrystal lattices on enhancement of surface light extraction,” Appl. Phys. Lett. 88(17), 171103 (2006). [CrossRef]
  14. S. Fan, P. R. Villeneuve, J. D. Joannopoulos, E. F. Schubert, “High extraction efficiency of spontaneous emission from slabs of photonic crystals,” Phys. Rev. Lett. 78(17), 3294–3297 (1997).
  15. M. Boroditsky, T. F. Krauss, R. Coccioli, R. Vrijen, R. Bhat, E. Yablonovitch, “Light extraction from optically pumped light-emitting diode by thin-slab photonic crystals,” Appl. Phys. Lett. 75(8), 1036–1038 (1999). [CrossRef]
  16. S. M. Jeong, F. Araoka, Y. Machida, K. Ishikawa, H. Takezoe, S. Nishimura, G. Suzaki, “Enhancement of normally directed light outcoupling from organic light-emitting diodes using nanoimprinted low-refractive-index layer,” Appl. Phys. Lett. 92(8), 083307 (2008). [CrossRef]
  17. J. Meyer, T. Winkler, S. Hamwi, S. Schmale, H.-H. Johannes, T. Weimann, P. Hinze, W. Kowalsky, T. Riedl, “Transparent inverted organic light-emitting diodes with a tungsten oxide buffer layer,” Adv. Mater. 20, 3839–3843 (2008).
  18. S. Nowy, J. Frischeisen, W. Brütting, “Simulation based optimization of light-outcoupling in organic light-emitting diodes,” Proc. SPIE 7415, 74151C (2009). [CrossRef]
  19. J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, 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]
  20. J.-H. Lee, S. Lee, J.-B. Kim, J. H. Jang, J.-J. Kim, “A high performance transparent inverted organic light emitting diode with 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile as an organic buffer layer,” J. Mater. Chem. 22(30), 15262–15266 (2012). [CrossRef]
  21. 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, J.-W. Kang, “Corrugated organic light emitting diodes for enhanced light extraction,” Org. Electron. 11(5), 711–716 (2010). [CrossRef]
  22. H.-H. Cho, B. Park, H.-J. Kim, J. Shim, S. Jeon, J.- Jeong, J.-J. Kim, “Planarization of nanopatterned substrates using solution process to enhance outcoupling efficiency of organic light emitting diodes,” Curr. Appl. Phys. 10(4), e139–e142 (2010). [CrossRef]
  23. K.-J. Byeon, E.-J. Hong, H. Park, J.-Y. Cho, S.-H. Lee, J. Jhin, J. H. Baek, H. Lee, “Full wafer scale nanoimprint lithography for GaN-based light-emitting diodes,” Thin Solid Films 519(7), 2241–2246 (2009).
  24. J. H. Kim, L. -M. Do, J.-H. Choi, J. Park, H. Lee, “Enhancement of outcoupling efficiency of organic light-emitting diodes using a planarized moth-eye structure on glass substrate,” Opt. Lett. 38(19), 3773–3775 (2013).
  25. Y.-C. Kim, S.-H. Cho, Y.-W. Song, Y.-J. Lee, Y.-H. Lee, Y. R. Do, “Planarized SiNx/spin-on-glass photonic crystal organic light-emitting diodes,” Appl. Phys. Lett. 89, 173502 (2006).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited