Journal of IKEEE (전기전자학회논문지)

Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
권호 표지
DOI QR코드

DOI QR Code

Eco-friendly External Light Extraction Films for Enhanced Out-Coupling Efficiency of Organic Light Emitting Diodes

유기발광다이오드의 광효율 향상을 위한 친환경 외부광추출 필름

  • Sora Han (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Baeksang Sung (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Dasol Kim (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Jinhwa Kim (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Seungwan Woo (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Jooho Lee (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Seung-Yo Baek (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Mijin Won (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Chul Woong Joo (Reality Display Research Section, Electronics and Telecommunications Research Institute (ETRI)) ;
  • Joo Won Han (Department of Smart Green Technology Engineering, Pukyong National University) ;
  • Yong Hyun Kim (Department of Smart Green Technology Engineering, Pukyong National University) ;
  • Dongsoo Kim (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Jae-Hyun Lee (Department of Creative Convergence Engineering, Hanbat National University) ;
  • Jonghee Lee (Department of Creative Convergence Engineering, Hanbat National University)
  • Received : 2023.04.21
  • Accepted : 2023.06.20
  • Published : 2023.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, we fabricated external out-coupling films for organic light emitting diodes (OLEDs) using ecofriendly materials, hydroxyethyl cellulose (HEC) and glycerol to improve the light extraction efficiency of OLEDs. HEC and glycerol-based microlens array (GHEC MLA) films were fabricated by imprinting method. The effect of GHEC MLA film on the external quantum and current efficiency of OLEDs were evaluated, and we found that the light-emitting performances of devices with the GHEC MLA film were improved by approximately 20% compared to those without the film. Furthermore, the GHEC MLA film exhibited excellent dissociation properties, completely dissolving in water within a few minutes, thus establishing its eco-friendliness. Hence, we propose that this GHEC MLA film could be employed as an eco-friendly and non-toxic light extraction film for next-generation OLEDs.

본 연구에서는 친환경 소재인 hydroxyethyl cellulose(HEC)와 glycerol을 활용하여 유기발광다이오드(OLED : organic light emitting diode)의 광효율 향상을 위한 외부 광추출 필름을 제작했다. 기존 microlens array(MLA) 몰드에 HEC 및 glycerol 기반 소재를 임프린팅하여 GHEC MLA 외부 광추출 필름을 제작하였다. GHEC MLA 필름이 OLED 소자의 외부양자효율 및 전류효율에 미치는 효과를 평가한 결과, GHEC MLA 필름을 부착하지 않은 소자에 비해 약 20% 향상됨을 확인했다. 또한, GHEC MLA 필름은 수 분 내로 물에 완전히 해리되는 우수한 친환경 특성을 입증하였다. 이를 통해 친환경 및 무독성의 GHEC MLA 필름은 차세대 OLED 광효율 향상 기술에 적용되어 활용될 수 있음을 제안한다.

Keywords

Acknowledgement

The authors acknowledge financial support from the Basic Science Research program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1A6A1A03026005 and 2022R1A2C1004286), and by Korea Institute for Advancement of Technology(KIAT) grant funded by the Korea Government(MOTIE) (P0012744, The Competency Development Program for Industry Specialist).

References

  1. A. Kim, G. H. Lee, J-H. Lee, "Enhancement of out-coupling efficiency of flexible organic lightemitting diodes fabricated on an MLA-patterned parylene substrate," Organic Electronics, vol.71, no.25, pp.246-250, 2019. DOI: 10.1016/j.orgel.2019.05.025
  2. S. W. Woo, J. Lee, B. Sung, A. Gasonoo, J. Cho, S-Y. Lee, S. J. Lee, Y-S. Lee, S-Y. Baek, J. Kim, Y. H. Kim, J-H. Lee, M-H. Kim, J. Lee, "Improved out-coupling efficiency of organic light-emitting diodes using micro-sized perovskite crystalline template," Organic Electronics, vol.108, 2022. DOI: 10.1016/j.orgel.2022.106580
  3. R. Shinar and J. Shinar, "Light extraction from organic light emitting diodes (OLEDs)," Journal of Physics: Photonics, vol.4, no.3, 2022. DOI: 10.1088/2515-7647/ac6ea4
  4. M. C. Suh, B. P. Byung, B. W. Lim, N. S. Kim, "Preparation of randomly distributed micro-lens arrays fabricated from porous polymer film and their application as a light extraction component," Organic Electronics, vol.38, pp.316-322, 2016. DOI: 10.1016/j.orgel.2016.08.029
  5. K. Saxena, V. K. Jain, D-S. Metha, "A review on the light extraction techniques in organic electroluminescent devices," Optical Materials, vol.32, pp.221-233, 2009. DOI: 10.1016/j.optmat.2009.07.014
  6. J-H. Han, J. Moon, D-H. Cho, J-W. Shin, H. Y. Chu, J-I. Lee, N. S. Cho & J. Lee, "Luminescence enhancement of OLED lighting panels using a microlens array film," Journal of Information Display, vol.19, no.4, pp.179-184, 2018. DOI: 10.1080/15980316.2018.1531073
  7. F. Galeotti, W. Mroz, G. Scavia, B. Chiara, "Microlens arrays for light extraction enhancement in organic light-emitting diodes: A facile approach," Organic Electronics, vol.14, no.1, pp.212-218, 2013. DOI: 10.1016/j.orgel.2012.10.034
  8. 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
  9. G. Zhal, W. Zhu, L. Huang, C. Yi & K. Ding, "Enhanced light extraction from green organic light-emitting diodes by attaching a high-haze random-bowls textured optical film," J. Phys. D: Appl. Phys., vol.53, p.8, 2020. DOI: 10.1088/1361-6463/ab9fc3
  10. M. lrimia-Vladu, "Green" electronics: biodegradable and biocompatible materials and devices for sustainable future," The Royal Society of Chemistry, vol.43, pp.588-610, 2014. https://doi.org/10.1039/C3CS60235D
  11. A. S. Khurd, B. Kandasubramanian, "A systematic review of cellulosic material for green electronics devices," Carbohydrate Polymer Technologies and Applications, vol.4, 2022. DOI: 10.1016/j.carpta.2022.100234
  12. Z. Fang, H. Zhang, S. Qiu, Y. Kuang, J. Zhou, Y. Lan, C. Sun, G. Li, S. Gong, Z. Ma, "Versatioe Wood Cellulose for Biodegradable Electronics," Adv.Mater. Technol., vol.6, 2021. DOI: 10.1002/admt.202000928
  13. B. Pang, G. Jliang, J. Zhou, Y. Ahu, W. Cheng, D. Zhao, K. Wang, G. Xu and H. Yu, "Molecular-Scale Design of Cellulose-Based Functional Materials for Flexible Electronic Devices," Adv. Electron.Mater, vol.7, 2021. DOI: 10.1002/aelm.202000944
  14. R. Tong, G Chen, J. Tian, M. He, "Highly transparent, weakly hydrophilic and biodegradable cellulose film for flexible electroluminescent devices," Carbohydrate Polymers, vol.227, 2020. DOI: 10.1016/j.carbpol.2019.115366
  15. A. S. Khurd, B. Kandasubramanian, "A systematic review of cellulosic material for green electronics devices," Carbohydrate Polymer Technologies and Applications, vol4, 2022. DOI: 10.1016/j.carpta.2022.100234
  16. M. Hao, L. Li, S. Wang, F. Sun, Y. Bai, Z. Cao, C. Qu & T. Zhang, "Stretchable, self-healing, transient macromolecular elastomeric gel for wearable electronics," Microsystems & Nanoengineering, vol.5, no.9, pp.5-9, 2019. DOI: 10.1038/s41378-019-0047-4
  17. Y. Han, C-K. Moon, K. Kim, H. Lee, J-J. Kim, "Random organic nano-textured microstructures formed by photoexcitation for light extraction of blue OLEDs," Organic Electronics, vol.87, 2020. DOI: 10.1016/j.orgel.2020.105892
  18. J. H. Lee, S. Kang, N-M. Park, J-W. Shin, C. W. Joo, J. Lee. S-D. Ahn, S-Y. Kang & J. Moon, "Porous cellulose paper as a light out coupling medium for organic light-emitting diodes," Journal of Information Display, vol.19, no.4, pp.171-177, 2018. DOI: 10.1080/15980316.2018.1527260
  19. J-H. Lee, Y-H. Ho, H-Y. Lin, J-H. Fang, S-C. Hsu, J-R. Lin & M-K. Wei, "Efficiency improvement and image quality of organic light-emitting display by attaching cylindrical microlens arrays," OPTICS EXPRESS, vol.16, no.26, 2008. DOI: 10.1364/OE.16.021184
  20. N. Jurgensen, B. Fritz, A. Mertens, J-N. Tisserant, M. Kolle, G. Gomard, G. Hernandez-Sosa, "A Single-Step Hot Embossing Process for Integration of Microlens Arrays in Biodegradable Substrates for Improved Light Extraction of Light-Emitting Devices," Adv. Mater. Technol., vol.6, no.2, 2021. DOI: 10.1002/admt.201900933
  21. C-H. Shin, E. Y. Shin, M-H. Kim, J-H. Lee & Y. Choi, "Nanoparticle scattering layer for improving light extraction efficiency of organic light emitting diodes," OPTICS EXPRESS, vol.23, no.3, pp.133-139, 2015. DOI: 10.1364/OE.23.00A133