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Title: Site-dependent charge transfer at the Pt(111)-ZnPc interface and the effect of iodine

The electronic structure of ZnPc, from sub-monolayers to thick films, on bare and iodated Pt(111) is studied by means of X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and scanning tunneling microscopy. Our results suggest that at low coverage ZnPc lies almost parallel to the Pt(111) substrate, in a non-planar configuration induced by Zn-Pt attraction, leading to an inhomogeneous charge distribution within the molecule and an inhomogeneous charge transfer to the molecule. ZnPc does not form a complete monolayer on the Pt surface, due to a surface-mediated intermolecular repulsion. At higher coverage ZnPc adopts a tilted geometry, due to a reduced molecule-substrate interaction. Our photoemission results illustrate that ZnPc is practically decoupled from Pt, already from the second layer. Pre-deposition of iodine on Pt hinders the Zn-Pt attraction, leading to a non-distorted first layer ZnPc in contact with Pt(111)-I(√3×√3) or Pt(111)-I(√7×√7), and a more homogeneous charge distribution and charge transfer at the interface. On increased ZnPc thickness iodine is dissolved in the organic film where it acts as an electron acceptor dopant.
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4]
  1. KTH Royal Institute of Technology, ICT MNF Materials Physics, Electrum 229, 16440 Kista (Sweden)
  2. Department of Applied Physics, Biological Physics, Chalmers University of Technology, Fysikgränd 3, 412 96 Göteborg (Sweden)
  3. Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala (Sweden)
  4. Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, St Lucia QLD 4072 (Australia)
Publication Date:
OSTI Identifier:
22252964
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; BINDING ENERGY; CHARGE DISTRIBUTION; DEPOSITION; ELECTRONIC STRUCTURE; ELECTRONS; FILMS; INTERACTIONS; IODINE; LAYERS; PHOTOEMISSION; SCANNING TUNNELING MICROSCOPY; SUBSTRATES; SURFACES; THICKNESS; X-RAY PHOTOELECTRON SPECTROSCOPY; X-RAY SPECTROSCOPY