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http://dx.doi.org/10.4313/JKEM.2014.27.6.377

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

Seo, Yu-Seok (Department of Materials Engineering, Soonchunhyang University)
Moon, Dae-Gyu (Department of Materials Engineering, Soonchunhyang University)
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.27, no.6, 2014 , pp. 377-382 More about this Journal
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.
Keywords
OLED; Phosphorescence; Spacer; Energy transfer; Diffusion;
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