Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
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Green Phosphorescent OLED Without a Hole/Exciton Blocking Layer Using Intermixed Double Host and Selective Doping

  • Kim, Won-Ki (Department of Electronics Engineering, Dankook University) ;
  • Kim, Hyung-Seok (Department of Electronics Engineering, Dankook University) ;
  • Shin, Hyun-Kwan (Department of Electronics Engineering, Dankook University) ;
  • Jang, Ji-Geun (Department of Electronics Engineering, Dankook University)
  • Published : 2009.05.27
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Abstract

Simple and high efficiency green phosphorescent devices using an intermixed double host of 4, 4', 4"-tris(N-carbazolyl) triphenylamine [TCTA], 1, 3, 5-tris (N-phenylbenzimiazole-2-yl) benzene [TPBI], phosphorescent dye of tris(2-phenylpyridine)iridium(III) [$Ir(ppy)_3$], and selective doping in the TPBI region were fabricated, and their electro luminescent characteristics were evaluated. In the device fabrication, layers of $70{\AA}$-TCTA/$90{\AA}$-$TCTA_[0.5}TPBI_{0.5}$/$90{\AA}$-TPBI doped with $Ir(ppy)_3$ of 8% and an undoped layer of $50{\AA}$-TPBI were successively deposited to form an emission region, and SFC137 [proprietary electron transporting material] with three different thicknesses of $300{\AA}$, $500{\AA}$, and $700{\AA}$ were used as an electron transport layer. The device with $500{\AA}$-SFC137 showed the luminance of $48,300\;cd/m^2$ at an applied voltage of 10 V, and a maximum current efficiency of 57 cd/A under a luminance of $230\;cd/m^2$. The peak wavelength in the electroluminescent spectral and color coordinates on the Commission Internationale de I'Eclairage [CIE] chart were 512 nm and (0.31, 0.62), respectively.

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References

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