Lower Hole-injection barrier between pentacene and HDT-modified Gold with lowered workfunction

  • Hong, Ki-Pyo (Department of Chemical Engineering, Pohang University of Science and Technology) ;
  • Lee, Jong-Won (Department of Chemical Engineering, Pohang University of Science and Technology) ;
  • Yang, Sang-Yoon (Department of Chemical Engineering, Pohang University of Science and Technology) ;
  • Shin, Kwon-Woo (Department of Chemical Engineering, Pohang University of Science and Technology) ;
  • Jeon, Ha-Young (Department of Chemical Engineering, Pohang University of Science and Technology) ;
  • Kim, Se-Hyun (Department of Chemical Engineering, Pohang University of Science and Technology) ;
  • Park, Chan-Eon (Department of Chemical Engineering, Pohang University of Science and Technology)
  • Published : 2006.10.13

Abstract

Through ultra-violet photoemission spectroscopy in-situ experiment, 0.67 eV energy barrier between 1-hexadecanethiol (HDT)-modified gold and pentacene was observed, which was 0.03 eV smaller than the energy barrier between bare gold and pentacene despite HDT modified gold had 0.8 eV lower work function than that of bare gold. This result is opposed to the idea that increasing the work function a metal decreases the energy barrier. This can be explained by two factors. One is the absence of interface dipole, which is observed in pentacene deposited on gold. The other is reduced ionization energy which can be explained through polarization energy or electronic splitting of molecular orbital with more crystalline structure observed through X-ray diffraction patterns.

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