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http://dx.doi.org/10.7471/ikeee.2020.24.1.140

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)
Publication Information
Journal of IKEEE / v.24, no.1, 2020 , pp. 140-146 More about this Journal
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.
Keywords
polymer dispersed liquid crystal; OLED; out-coupling efficiency; haze; light extraction;
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1 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   DOI
2 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
3 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   DOI
4 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   DOI
5 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   DOI
6 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
7 S. Kunic and Z. Sego, "OLED technology and displays," Proc. ELMAR, pp.31-35, 2012.
8 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   DOI
9 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.   DOI
10 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.   DOI
11 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
12 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   DOI
13 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   DOI
14 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   DOI
15 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
16 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   DOI
17 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   DOI
18 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.   DOI
19 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   DOI
20 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   DOI
21 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   DOI
22 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   DOI
23 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   DOI
24 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   DOI