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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-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-1 which slightly shift to 34.2 and 40.0 cd A-1 at 1000 cd m-2 are 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
Volume11
Issue number2
DOIs
Publication statusPublished - Feb 2010

Scopus Subject Areas

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

User-Defined Keywords

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

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