Inhomogeneous charge transfer within monolayer zinc phthalocyanine absorbed on TiO2(110)
2012 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 136, no 15, 154703- p.Article in journal (Refereed) Published
The d-orbital contribution from the transition metal centers of phthalocyanine brings difficulties to understand the role of the organic ligands and their molecular frontier orbitals when it adsorbs on oxide surfaces. Here we use zinc phthalocyanine (ZnPc)/TiO2(110) as a model system where the zinc d-orbitals are located deep below the organic orbitals leaving room for a detailed study of the interaction between the organic ligand and the substrate. A charge depletion from the highest occupied molecular orbital is observed, and a consequent shift of N1s and C1s to higher binding energy in photoelectron spectroscopy (PES). A detailed comparison of peak shifts in PES and near-edge X-ray absorption fine structure spectroscopy illustrates a slightly uneven charge distribution within the molecular plane and an inhomogeneous charge transfer screening between the center and periphery of the organic ligand: faster in the periphery and slower at the center, which is different from other metal phthalocyanine, e. g., FePc/TiO2. Our results indicate that the metal center can substantially influence the electronic properties of the organic ligand at the interface by introducing an additional charge transfer channel to the inner molecular part.
Place, publisher, year, edition, pages
2012. Vol. 136, no 15, 154703- p.
Binding energy, Electronic properties, Ligands, Monolayers, Nitrogen compounds, Photoelectron spectroscopy, Quantum chemistry, Titanium dioxide, Transition metals, X ray absorption fine structure spectroscopy, Zinc compounds
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-47336DOI: 10.1063/1.3699072ISI: 000303147000034ScopusID: 2-s2.0-84860168047OAI: oai:DiVA.org:kth-47336DiVA: diva2:454798
FunderSwedish Research Council
QC 20120521. Updated from submitted to published.2011-11-082011-11-082013-12-03Bibliographically approved