title: Site-dependent charge transfer at the Pt(111)-ZnPc interface and the effect of iodine.
abstract: 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.affiliation: KTH Royal Institute of Technology, ICT MNF Materials Physics, Electrum 229, 16440 Kista, Sweden.
authors.forename: Sareh
authors.initials: S
authors.lastname: Ahmadi
authors.affiliation: Department of Applied Physics, Biological Physics, Chalmers University of Technology, Fysikgränd 3, 412 96 Göteborg, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Agnarsson
authors.affiliation: Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden.
authors.forename: Ieva
authors.initials: I
authors.lastname: Bidermane
authors.affiliation: KTH Royal Institute of Technology, ICT MNF Materials Physics, Electrum 229, 16440 Kista, Sweden.
authors.forename: Bastian M
authors.initials: BM
authors.lastname: Wojek
authors.affiliation: KTH Royal Institute of Technology, ICT MNF Materials Physics, Electrum 229, 16440 Kista, Sweden.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Noël
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, St Lucia QLD 4072, Australia.
authors.forename: Chenghua
authors.initials: C
authors.lastname: Sun
authors.affiliation: KTH Royal Institute of Technology, ICT MNF Materials Physics, Electrum 229, 16440 Kista, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Göthelid
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D004583:Electrons; D007211:Indoles / Q000737:chemistry; D007455:Iodine / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D009942:Organometallic Compounds / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D010984:Platinum; C063072:zinc(II) phthalocyanine trisulfonic acid; D002244:Carbon; D007455:Iodine