A yellow-emitting iridium complex for use in phosphorescent multiple-emissive-layer white organic light-emitting diodes with high color quality and efficiency

Xiao Ming Yu, Gui Jiang Zhou, Ching Shan Lam, Wai Yeung Wong, Xiu Ling Zhu, Jia Xin Sun, Man Wong, Hoi Sing Kwok

Research output: Journal article publicationJournal articleAcademic researchpeer-review

91 Citations (Scopus)


A cyclometalated iridium(III) complex containing 2-(9,9-diethylfluoren-2-yl)pyridine [Ir(Flpy)3] was prepared and used in the fabrication of both yellow and white organic light-emitting diodes (OLEDs). A hole-blocking material has been used as a hole barrier layer in-between different emission layers, helping the formation of the hole limitation region. With the proper position of a hole barrier layer and the construction of a four-emission-layer structure involving the use of [Ir(Flpy)3], the resulting WOLED shows sound device performance as well as very stable color even at high luminances. Such WOLEDs have been demonstrated to reveal superior white light color stability/efficiency trade-off optimization. The Commission Internationale de L'Eclairage (CIE) coordinate differences Δx and Δy are confined to ±0.015 when the luminance increases from 13 to 14806 cd/m2. The color rendering index (CRI) of the device is also very good, which varies only from 86 to 87 by changing from the normal direction to 80° off-normal at 12 V. The peak electrophosphorescence efficiency can reach as high as 24.6 cd/A at 168 cd/m2and it can still be kept at 17.2 cd/A at 10834 cd/m2. Such outstanding performance renders this all-phosphor WOLED very attractive as a white light source for illumination applications, which typically demand high efficiency, high CRI, and stable color in high brightness work conditions.
Original languageEnglish
Pages (from-to)1518-1527
Number of pages10
JournalJournal of Organometallic Chemistry
Issue number8-9
Publication statusPublished - 15 Apr 2008
Externally publishedYes


  • Iridium
  • Luminescence
  • Metal complex
  • Organic light-emitting diode
  • Phosphorscence

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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