The Potential of X-ray Photoelectron Spectroscopy for Determining Interface Dipoles of Self-Assembled Monolayers

Thomas C. Taucher, Egbert Zojer

Research output: Contribution to journalArticlepeer-review


In the current manuscript we assess to what extent X-ray photoelectron spectroscopy (XPS) is a suitable tool for probing the dipoles formed at interfaces between self-assembled monolayers and metal substrates. To that aim, we perform dispersion-corrected, slab-type band-structure calculations on a number of biphenyl-based systems bonded to an Au(111) surface via different docking groups. In addition to changing the docking chemistry (and the associated interface dipoles), the impacts of polar tail group substituents and varying dipole densities are also investigated. We find that for densely packed monolayers the shifts of the peak positions of the simulated XP spectra are a direct measure for the interface dipoles. In the absence of polar tail group substituents they also directly correlate with adsorption-induced work function changes. At reduced dipole densities this correlation deteriorates, as work function measurements probe the difference between the Fermi level of the substrate and the electrostatic energy far above the interface, while core level shifts are determined by the local electrostatic energy in the region of the atom from which the photoelectron is excited.

Original languageEnglish
Article number5735
JournalApplied Sciences
Issue number17
Publication statusPublished - Sept 2020


  • Band-structure calculation
  • Collective electrostatics
  • Density-functional theory
  • DFT
  • SAM
  • Self-assembled monolayer
  • X-ray photoelectron spectroscopy
  • XPS

ASJC Scopus subject areas

  • Engineering(all)
  • Instrumentation
  • Materials Science(all)
  • Fluid Flow and Transfer Processes
  • Process Chemistry and Technology
  • Computer Science Applications

Fields of Expertise

  • Advanced Materials Science


  • NAWI Graz

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