Modification of Charge Transfer and Energy Level Alignment at Organic/TiO2 Interfaces
2009 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 31, 13765-13771 p.Article in journal (Refereed) Published
Adsorption of titanyl phthalocyanine (TiOPc) on rutile TiO2(110) modified by a set of pyridine derivatives (2,2'-bipyridine, 4,4'-bipyridine, and 4-tert-butyl pyridine) has been investigated using synchrotron radiation based X-ray photoelectron spectroscopy (XPS). For the unmodified TiOPc/TiO2 system, a strong charge transfer is observed from the first layer TiOPc into the substrate, which leads to a molecular layer at the interface with a depleted highest occupied molecular orbital (HOMO). However, precovering the TiO2 surface with a saturated pyridine monolayer effectively reduce this process and leave the TiOPc in a less perturbed molecular state. Furthermore, the TiOPc HOMO and core levels are observed at different binding energies ranging by 0.3 eV on the three pyridine monolayers, which is ascribed to differences in surface potentials set up by the different pyridine/TiO2 systems.
Place, publisher, year, edition, pages
2009. Vol. 113, no 31, 13765-13771 p.
electronic-structure, titanyl phthalocyanine, tio2(110)-(1x1) surface, stm observation, solar-cells, thin-film, metal, pyridine, molecules, layer
IdentifiersURN: urn:nbn:se:kth:diva-18640DOI: 10.1021/jp902814dISI: 000268478700047ScopusID: 2-s2.0-68749107094OAI: oai:DiVA.org:kth-18640DiVA: diva2:336687
QC 201005252010-08-052010-08-052011-11-14Bibliographically approved