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Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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Polymer Dispersed Liquid Crystal for Enhanced Light Out-Coupling Efficiency of Organic Light Emitting Diodes

  • Gasonoo, Akpeko (Department of Electronic Engineering, Hanbat National University) ;
  • Ahn, Hyeon-Sik (Department of Electronic Engineering, Hanbat National University) ;
  • Lee, Jonghee (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Kim, Min-Hoi (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Lee, Jae-Hyun (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Choi, Yoonseuk (Department of Electronic Engineering, Hanbat National University)
  • Received : 2020.03.06
  • Accepted : 2020.03.20
  • Published : 2020.03.31
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Abstract

We investigated light extraction film based on polymer dispersed liquid crystal (PDLC) for application in organic light emitting diodes (OLEDs). At least 30 seconds of direct UV irradiation process for curing PDLC film on a bottom-emitting OLEDs was successfully achieved without damage on the intrinsic properties of the OLED. We demonstrated that high haze and transmittance can be tuned simultaneously by controlling the UV curing time. By adding PDLC as an external layer without any additional treatment, the light scattering and extraction is increased. Consequently, a PDLC scattering film with 89.8% and 59.9 of total transmittance and haze respectively, achieved about 16% of light intensity enhancement from integrating sphere measurement.

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References

  1. N. Thejo Kalyani and S. J. Dhoble, "Organic light emitting diodes: Energy saving lighting technology-A review," Renewable Sustainable Energy Rev., Vol.16, No.5, pp.2696-2723, 2012. DOI: 10.1016/j.rser.2012.02.021
  2. T.-H. Han, Y. Lee, M.-R. Choi, S.-H. Woo, S.-H. Bae, B. H. Hong, J.-H. Ahn and T.-W. Lee, "Extremely efficient flexible organic light-emitting diodes with modified graphene anode," Nat. Photonics, Vol.6, pp.105-110, 2012. https://doi.org/10.1038/nphoton.2011.318
  3. H. Sasabe and J. Kido, "Development of high performance OLEDs for general lighting," J. Mater. Chem. C, Vol.1. No.9, pp.1699-1707, 2013. https://doi.org/10.1039/c2tc00584k
  4. S. Kunic and Z. Sego, "OLED technology and displays," Proc. ELMAR, pp.31-35, 2012.
  5. C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes," Appl. Phys. Lett. Vol.51, No.12, pp.91915, 1987. DOI: 10.1063/1.98799
  6. R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Dohler, B. Dutta, and G. Borghs, "Light-emittingdiodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes," Appl. Phys. Lett. Vol.74, No.16, pp.2256-2258, 1999. DOI: 10.1063/1.123817
  7. K. Saxena, V. K. Jain, and D. S. Mehta, "A review on the light extraction techniques in organic electroluminescent devices," Optical Materials, Vol.32, No.1, pp.221-233, 2009. DOI: 10.1016/j.optmat.2009.07.014
  8. H.-W. Chang, K.-C. Tien, M.-H. Hsu, Y.-H. Huang, M.-S. Lin, C.-H. Tasi, Y.-T. Tasi, and C.-C. Wu, "Organic light-emitting devices integrated with internal scattering layers for enhancing optical out-coupling," J. Soc. Inf. of Disp., Vol.19, No.2, pp.196-204, 2011. DOI: 10.1889/JSID19.2.196
  9. H.-W. Chang, J.-H. Lee, S. Hofmann, Y. H. Kim, L. Muller-Meskamp, B. Lussem, C.-C. Wu, K. Leo, and M. C. Gather, "Nano-particle based scattering layers for optical efficiency enhancement of organic light-emitting diodes and organic solar cells," J. Appl. Phys., Vol.113, No.20, pp.204-502, 2013. DOI: 10.1063/1.4807000
  10. N. K. Patel, S. Cina, and J. H. Burroughes, "High-efficiency organic light-emitting diodes," IEEE J. Sel. Top. Quantum Electron. Vol.8, No.2, pp.346-361, 2002. DOI: 10.1109/2944.999190
  11. S. Moller and S. R. Forrest, "Improved light out-coupling in organic light emitting diodes employing ordered microlens arrays," J. Appl. Phys., Vol.91, No.5, pp.3324-3327, 2002. DOI: 10.1063/1.1435422
  12. A. Kim, G. Huseynova, J. Lee, J.-H. Lee, "Enhancement of out-coupling efficiency of flexible organic light-emitting diodes fabricated on an MLA-patterned parylene substrate," Organic Electronics, Vol.71, pp.246-250, 2019. DOI: 10.1016/j.orgel.2019.05.025
  13. Feng Li, Xiao Li, J. Zhang, B. Yang, "Enhanced light extraction from organic light-emitting devices by using microcontact printed silica colloidal crystals," Organic Electronics, Vol.8, No.5, pp.635-639, 2007. DOI: 10.1016/j.orgel.2007.06.001
  14. J.-W. Shin, D.-H. Cho, J. Moon, C. W. Joo, J. Lee, J. W. Huh, S. K. Park, J.-H. Han, N. S. Cho, J. Hwang, H. Y. Chu, and J.-I. Lee, "Random nanostructure scattering layer for suppression of microcavity effect and light extraction in OLEDs," Opt. Letters, Vol.39, No.12, pp.3527-3530, 2007. https://doi.org/10.1364/OL.39.003527
  15. 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. Express, Vol.14, No.14, pp.6564-6571, 2006. DOI: 10.1364/OE.14.006564
  16. Y.-J. Lee, S.-H. Kim, J. Huh, G.-H. Kim, Yong-Hee Lee, S.-H. Cho, Y.-C. Kim, and Y. R. Do, "A high-extraction-efficiency nanopatterned organic light-emitting diode," Appl. Phys. Lett., Vol.82, No.21, pp.3779-3781, 2003. DOI: 10.1063/1.1577823
  17. C.-H. Shin, E. Y. Shin, M.-H. Kim, J.-H. Lee, and Y. Choi, "Nanoparticle scattering layer for improving light extraction efficiency of organic light emitting diodes," Opt. Express, Vol.23, No.3, pp.A133-A139, 2015. DOI: 10.1364/OE.23.00A133
  18. D.-Y. Zhou, X.-B. Shi, C.-H. Gao, S.-D. Cai, Y. Jin, L.-S. Liao, "Light extraction enhancement from organic light-emitting diodes with randomly scattered surface fixture," Applied Surface Science, Vol.314, pp.858-863, 2014. DOI: 10.1016/j.apsusc.2014.07.001
  19. J. Jiang, G. Mcgraw, R. Ma, J. Brown, and D.-K. Yang, "Selective scattering polymer dispersed liquid crystal film for light enhancement of organic light emitting diode," Opt. Express, Vol.25, No.4, pp.3327-3335, 2017. DOI: 10.1364/OE.25.003327
  20. J. W. Doane, A. Golemme, J. L. West, J. B. Whitehead, and B. G. Wu, "Polymer dispersed liquid crystals for display application," Mol. Cryst. Liquid Cryst., Vol.165, No.1, pp.511-532, 1988. DOI: 10.1080/00268948808082211
  21. S. C. Sharma, "A review of the electro-optical properties and their modification by radiation in polymerdispersed liquid crystals and thin films containing CdSe/ZnS quantum dots," Mater. Sci. Eng: B, Vol.168, No.1-3, pp.5-15, 2010. DOI: 10.1016/j.mseb.2010.01.014
  22. Y. Kim, D. Jung, S. Jeong, K. Kim, W. Choi, Y. Seo, "Optical properties and optimized conditions for polymer dispersed liquid crystal containing UV curable polymer and nematic liquid crystal," Current Applied Physics, Vol.15, No.3, pp.292-297, 2015. DOI: 10.1016/j.cap.2014.12.027
  23. J. Lee, N. Chopra, and F. So, "Cavity effects on light extraction in organic light emitting devices," Appl. Phys. Lett. Vol.92, No.3, pp.033303, 2008. DOI: 10.1063/1.2830820
  24. H.-W. Chang, K.-C. Tien, M.-H. Hsu, Y.-H. Huang, M.-S. Lin, C.-H. Tsai, Y.-T. Tsai, and C.-C. Wu, "Organic light-emitting devices integrated with internal scattering layers for enhancing optical out-coupling," J. SID., Vol.19, No.2, pp.196-204, 2011. DOI: 10.1889/JSID19.2.196

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