Impact of an interface dipole layer on molecular level alignment at an organic-conductor interface studied by ultraviolet photoemission spectroscopy

S. Kera, Y. Yabuuchi, H. Yamane, H. Setoyama, K. K. Okudaira, A. Kahn, N. Ueno

Research output: Contribution to journalArticle

140 Scopus citations

Abstract

The effect of an interface dipole layer on the energy level alignment at organic-conductor interfaces is studied on a copper phthalocyanine (CuPc) monolayer/electric dipole layer/graphite system via ultraviolet photoemission spectroscopy (UPS) and metastable atom electron spectroscopy. An oriented monolayer of the OTi-phthalocyanine molecule, which has an electric dipole moment, is grown on graphite to yield a well-defined dipole layer with the vacuum side negatively charged. The CuPc monolayer is sequentially deposited on the dipole layer kept at 123 K. This weakly interacting system made of a very thin organic layer on top of a very thin dipole layer is in thermodynamic equilibrium. The UPS data from the system grown with and without the interface dipole layer show that the binding energy of the highest occupied state of the CuPc monolayer decreases when the dipole layer is inserted. The binding energy shift is in excellent agreement with the increase in vacuum level energy of the graphite substrate upon deposition of the dipole layer. The results show that the Fermi level of the CuPc shifts toward the valence states when the interface dipole layer is inserted.

Original languageEnglish (US)
Pages (from-to)085304-1-085304-6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume70
Issue number8
DOIs
StatePublished - Aug 1 2004

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Impact of an interface dipole layer on molecular level alignment at an organic-conductor interface studied by ultraviolet photoemission spectroscopy'. Together they form a unique fingerprint.

Cite this