Improving the optical properties of organic light-emitting diodes using random nanoscale rods with a double refractive index

Jin Ho Kwack, Ha Hwang, Junhee Choi, Younguk Choi, Young Wook Park, Byeong Kwon Ju

Research output: Contribution to journalArticle

Abstract

In this study, random nanoscale rods (RNRs) with a double refractive index were fabricated via spin coating, dry etching, and sputtering, which are processes that are extensively applied in industry. With regard to optical properties, the RNRs with a double refractive index (RNRsD) exhibited a total transmittance that was >90% in the visible range and an optical haze in the range of 42%-50% at a wavelength of 520 nm. Organic light-emitting diodes (OLEDs) with RNRsD, where SiO2 was deposited on the RNRs via radiofrequency sputtering, exhibited an enhancement of 34.5% in the external quantum efficiency compared with OLEDs with the bare substrate. Furthermore, the color variation of the OLEDs with the optimal RNRsD with respect to a change in the viewing angle was improved from color coordinates of Δ(x, y) = (0.032, 0.034) to Δ(x, y) = (0.014, 0.014). Therefore, the proposed film can be used as a scattering layer for enhancing the light extraction and viewing angle of OLEDs by reducing the substrate mode light loss and changing the direction of light. In addition to using a low-Temperature fabrication process that does not employ a photomask and a lithographic template, the proposed method is applicable to flexible devices because it uses a polymer and a thin inorganic film.

Original languageEnglish
Article number335205
JournalNanotechnology
Volume31
Issue number33
DOIs
Publication statusPublished - 2020 Aug 14

Keywords

  • light extraction
  • organic light-emitting diodes (OLEDs)
  • random nanoscale rods
  • substrate mode
  • viewing angle

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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