Reduced efficiency roll-off in highly efficient and color-stable hybrid WOLEDs: The influence of triplet transfer and charge-transport behavior on enhancing device performance

Qi Wang, Cheuk Lam Ho, Yongbiao Zhao, Dongge Ma, Wai Yeung Wong, Lixiang Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

77 Citations (Scopus)

Abstract

By wisely utilizing combinations of exciton-managed orange-phosphorescence/sky blue-fluorescence, we report on high-efficiency white organic light-emitting diodes (WOLEDs) with high color-stability together with reduced efficiency roll-off. Two WOLEDs with the peak current efficiencies of 34.5 and 42.5 cd A-1which slightly shift to 34.2 and 40.0 cd A-1at 1000 cd m-2are demonstrated. Systematic investigations focused on the effects of hole-injection buffer layer, thickness of emitting-layer (EML) and the stepwise-doping profile of orange phosphorescent EML on the device performance have been performed. It is evidently shown that careful management of the triplet/singlet excitons and charge-carriers is key to realizing such high performance of the devices. The results will beyond doubt be helpful to the design of both material and device structure for high-performance WOLEDs and next-generation solid-state lighting sources.
Original languageEnglish
Pages (from-to)238-246
Number of pages9
JournalOrganic Electronics: physics, materials, applications
Volume11
Issue number2
DOIs
Publication statusPublished - 1 Feb 2010
Externally publishedYes

Keywords

  • Carbazole
  • Iridium complexes
  • Organic light-emitting diodes
  • Triplet emission
  • White light

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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