Development of Very High Luminance p–i–n Junction-Based Blue Fluorescent Organic Light-Emitting Diodes

Research output: Contribution to journal › Research article › Contributed › peer-review

Contributors

  • Yali Deng - , University of St Andrews (Author)
  • Caroline Murawski - , Kurt Schwabe Institut Meinsberg, University of St Andrews (Author)
  • Changmin Keum - , University of St Andrews (Author)
  • Kou Yoshida - , University of St Andrews (Author)
  • Ifor D. W. Samuel - , University of St Andrews (Author)
  • Malte C. Gather - , University of St Andrews (Author)

Abstract

Abstract Organic light-emitting diodes (OLEDs) can emit light over much larger areas than their inorganic counterparts, offer mechanical flexibility, and can be readily integrated on various substrates and backplanes. However, the amount of light they emit per unit area is typically lower and the required operating voltage is higher, which can be a limitation for emerging applications of OLEDs, e.g., in outdoor and high-dynamic-range displays, biomedical devices, or visible-light communication. Here, high-luminance, blue-emitting (?peak = 464 nm), fluorescent p?i?n OLEDs are developed by combining three strategies: First, the thickness of the intrinsic layers in the device is decreased to reduce internal voltage loss. Second, different electron-blocking layer materials are tested to recover efficiency losses resulting from this thickness reduction. Third, the geometry of the anode contact is optimized, which leads to a substantial reduction in the in-plane resistive voltage losses. The OLEDs retain a maximum external quantum efficiency of 4.4% as expected for an optimized fluorescent device and reach a luminance of 132 000 cd m?2 and an optical power density of 2.4 mW mm?2 at 5 V, a nearly eightfold improvement compared to the original reference device.

Details

Original languageEnglish
Article number1901721
JournalAdvanced optical materials
Volume8
Issue number6
Early online date20 Jan 2020
Publication statusPublished - 19 Mar 2020
Peer-reviewedYes
Externally publishedYes

External IDs

doi https://doi.org/10.1002/adom.201901721
Scopus 85078675519

Keywords

Keywords

  • CMOS-compatible devices, device dimensions, electron-blocking layer, high brightness, high current density, organic light-emitting diodes, resistance of anode contact