Enhanced light extraction from organic light-emitting diodes using a quasi-periodic nano-structure

Ju Sung Lee, Yong Sub Shim, Chan Hyuk Park, Ha Hwang, Cheol Hwee Park, Chul Woong Joo, Young Wook Park, Jonghee Lee, Byeong Kwon Ju

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Organic light-emitting diodes with a quasi-periodic nano-structure (QPS) were fabricated via a combination of laser interference lithography (LIL) and reactive ion etching (RIE). The LIL process was used to generate a periodic pattern, whereas the RIE process was used as a supplement to add randomness to the periodic pattern. The period of the fabricated periodic pattern was determined by finite difference time domain solutions. The height and density of the QPS were controlled by the RIE etching time and were optimized. The resulting quasi-periodic nanostructure comprised silicon dioxide (SiO 2 ) with a low refractive index (n = 1.4-1.5), and an external quantum efficiency enhancement of 18% was achieved using the QPS device, without any viewing angle problems or spectral distortion, which are serious drawbacks of periodic patterns.

Original languageEnglish
Article number085302
Issue number8
Publication statusPublished - 2019 Feb 22

Bibliographical note

Funding Information:
This work was supported by the Industry Technology R&D program of MOTIE/KEIT (10048317, Development of red and blue OLEDs with external quantum efficiency over 20% using delayed fluorescent materials), the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP) (No. 2016R1A2B4014073), the Basic Science Research program through the National Research Foundation of Korea (NRF) funded by the Ministry pf Edi-catopm (2018R1A6A1A03026005), and the KIAT (Korea Institute for Advancement of Technology) grant funded by the Korea Government (MOTIE: Ministry of Trade Industry and Energy). (No. P0001018, HRD program for Highly educated human resources development project on cutting-edge sensor technology for sensor industry acceleration).

Publisher Copyright:
© 2018 IOP Publishing Ltd.


  • distortion free spectrum
  • light extraction
  • organic light-emitting diodes (OLEDs)
  • quasi-periodic nanostructures

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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