Transactions on Electrical and Electronic Materials

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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White Organic Light Emitting Diodes using Red and Blue Phosphorescent Materials with Blocking Layer

  • Park, Jung-Hyun (Department of Information Display, Hong Ik University) ;
  • Kim, Gu-Young (Department of Information Display, Hong Ik University) ;
  • Lee, Seok-Jae (Department of Information Display, Hong Ik University) ;
  • Seo, Ji-Hyun (Department of Information Display, Hong Ik University) ;
  • Seo, Ji-Hoon (Department of Information Display, Hong Ik University) ;
  • Kim, Young-Kwan (Department of Information Display, Hong Ik University)
  • Published : 2007.10.31
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Abstract

High-efficiency white organic light-emitting diodes(WOLEDs) were fabricated with two emissive layers and an blocking layer was sandwiched between two phosphorescent dopants, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III(FIrpic) as the blue emission and a newly synthesized red phosphorescent material guest, bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate($(acppy)_2Ir(acac)$). This blocking layer prevented a T-T annihilation in a red emissive layer, and balanced with blue and red emission as blocking of hole carriers. The white device showed Commission Internationale d'Eclairage($CIE_{x,y}$) coordinates of (0.317, 0.425) at 22400 $cd/m^2$, a maximum luminance of 27300 $cd/m^2$ at 268 $mA/cm^2$, a maximum luminous efficiency and power efficiency of 26.9 cd/A and 18.6 lm/W.

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