Changing adsorption mode of FePc on TiO2(110) by surface modification with bipyridine
2008 (English)In: Journal of Chemical Physics, ISSN 0021-9606, Vol. 129, no 7, 074707- p.Article in journal (Refereed) Published
Surface modification of reactive oxide substrates to obtain a less strongly interacting template for dye adsorption may be a way to enhance performance in dye-sensitized solar cells. In this work, we have investigated the electronic and structural properties of 4,4(')-bipyridine (bipy) as modifier adsorbed on the TiO2(110) surface. The modified surface is then coated with iron phthalocyanine (FePc) and the properties of this heterostructure are investigated with synchrotron based photoelectron spectroscopy, x-ray absorption spectroscopy, and scanning tunneling microscopy. We find that a saturated monolayer consisting of standing bipy molecules with one nitrogen atom pointing outward is formed on the oxide surface. FePc adsorb in molecular chains along the  direction on top of bipy and ordered in a tilted arrangement with adjacent molecules partially overlapping. Already from the first layer, the electronic properties of FePc resemble those of multilayer films. FePc alone is oxidized on the TiO2(110) surface, but preadsorbed bipy prevents this reaction. The energy level lineup at the interface is clarified.
Place, publisher, year, edition, pages
2008. Vol. 129, no 7, 074707- p.
IdentifiersURN: urn:nbn:se:uu:diva-109124DOI: 10.1063/1.2969081ISI: 000258643300041OAI: oai:DiVA.org:uu-109124DiVA: diva2:248924