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Effects of PEDOT:PSS Buffer Layer in a Device Structure of ITO/PEDOT:PSS/TPD/Alq3/Cathode

  • Ahn, Joon-Ho (Department of Electrical Engineering, Kwangwoon University) ;
  • Lee, Joon-Ung (Department of Electrical Engineering, Kwangwoon University)
  • Published : 2005.02.01

Abstract

We have investigated the effects of hole-injection buffer layer in organic light-emitting diodes using poly(3,4-ethylenedioxythiophene):poly(stylenesulfonate)(PEDOT:PSS) in a device structure of $ITO/PEDOT:PSS/TPD/Alq_{3}/cathode$. Polymer PEDOT:PSS buffer layer was made by spin casting method. Current-voltage, luminance-voltage characteristics and efficiency of device were measured at room temperature with a variation of cathode materials; Al, LiF/Al, LiAl, and Ca/Al. The device with LiF/Al cathode shows an improvement of external quantum efficiency approximately by a factor of ten compared to that of Al cathode only device. Our observation shows that cathode is important in improving the efficiency of the organic light-emitting diodes.

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