Highly improved light extraction with a reduced spectrum distortion of organic light-emitting diodes composed by the sub-visible wavelength nano-scale periodic (∼250 nm) structure and micro-lens array

Kyung Bok Choi, Se Joong Shin, Tae Hyun Park, Hyun Jun Lee, Ju Hyun Hwang, Jung Ho Park, Bo Yeon Hwang, Young Wook Park, Byeong Kwon Ju

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Out-coupling enhanced organic light-emitting diodes (OLEDs) with micro-lens arrays and a nano-scale periodic light-extraction structure - a photonic crystal (PC) - utilizing laser interference lithography (LIL) are demonstrated. Generally, PC-based OLEDs suffer from a distorted and shifted spectrum, despite a highly improved intensity. However, in this study, we demonstrate PC-based OLEDs with a distortion-free spectrum and a highly improved out-coupling performance. It was found that spectrum distortion decreased with the pitch size of the PC. The PC-based OLED with a 250 nm pitch size showed a dramatically reduced spectral shift: International Commission on Illumination 1931 color coordinate of (Δ0.00, Δ0.00) and Δpeak wavelength of 0 nm as compared with the reference. Simultaneously, the external quantum efficiency and the power efficiency were enhanced by up to 178% and 264%, respectively, as compared with the reference. Moreover, through the LIL, simple and maskless processes were achieved for a light-extraction structure over a large area.

Original languageEnglish
Pages (from-to)111-117
Number of pages7
JournalOrganic Electronics
Volume15
Issue number1
DOIs
Publication statusPublished - 2014

Keywords

  • Laser interference lithography (LIL)
  • Micro-lens arrays
  • Nano-scale periodic pattern
  • Organic light-emitting diodes (OLEDs)
  • Out-coupling
  • Photonic crystal

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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