Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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방사광 가속기의 광전자 분광법을 이용한 전면 발광 유기발광 다이오드에서의 열중착 산화구리와 유기물 사이의 계면 dipole 에너지 및 정공 주입 효율에 대한 연구

  • Kim, Seong-Jun (Division of Advanced Materials Science and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH)) ;
  • Hong, Gi-Hyeon (Division of Advanced Materials Science and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH)) ;
  • Kim, Gi-Su (Division of Advanced Materials Science and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH)) ;
  • Lee, Il-Hwan (Division of Advanced Materials Science and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH)) ;
  • Lee, Jong-Ram (Division of Advanced Materials Science and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH))
  • Published : 2010.03.25
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Abstract

We report the enhancement of hole injection using thermally evaporated $CuO_x$ layer between Ag anode and 4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl ($\alpha$-NPD) in top-emitting organic light-emitting diode (TEOLED). The operation voltage at the current density of $1mA/cm^2$ of TEOLEDs decreased from 6.2 V to 5.0 V as the $CuO_x$ layer inserted between Ag and $\alpha$-NPD. $\alpha$-NPD was deposited in situ on Ag/$CuO_x$ and Ag anodes, and their interface dipole energies were quantitatively determined using synchrotron radiation photoemission spectroscopy. The dipole energy of Ag/$CuO_x$ was lower by 0.05 eV even though Ag/$CuO_x$ had a higher work function. The work function of Ag/$CuO_x$ is higher by 0.53 eV than that of Ag, resulting in a decrease of the turn-on voltage via reduction of hole injection barrier.

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