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Effects of Spacer Inserted Inside the Emission Layer on the Efficiency and Emission Characteristics of Phosphorescent Organic Light-emitting Diodes

발광층 내의 스페이서가 인광 OLED의 효율 및 발광 특성에 미치는 영향

  • Seo, Yu-Seok (Department of Materials Engineering, Soonchunhyang University) ;
  • Moon, Dae-Gyu (Department of Materials Engineering, Soonchunhyang University)
  • 서유석 (순천향대학교 신소재공학과) ;
  • 문대규 (순천향대학교 신소재공학과)
  • Received : 2014.03.14
  • Accepted : 2014.05.12
  • Published : 2014.06.01

Abstract

We have investigated the effects of spacer layer inserted between blue and red doped emission layers on the emission and efficiency characteristics of phosphorescent OLEDs. N,N'-di-carbazolyl-3,5-benzene (mCP) was used as a host layer. Iridium(III)bis[(4,6-di-fluorophenyl)- pyridinato-N,$C^2$']picolinate (FIrpic) and tris(1-phenyl-isoquinolinato-$C^2$,N)iridium(III) [Ir(piq)3] were used as blue and red dopants, respectively. The emission layer structure was mCP (1-x) nm/mCP:$Ir(piq)_3$ (5 nm, 10%)/mCP (x nm)/mCP:FIrpic (5 nm, 10%). The thickness of mCP spacer layer was varied from 0 to 15 nm. The emission from $Ir(piq)_3$ and the efficiency of the device were dominated by energy transfer from mCP host and FIrpic molecules, and by diffusion of mCP host triplet excitons.

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