4-tert-Butyl Pyridine Bond Site and Band Bending on TiO2(110)
2010 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 5, 2315-2320 p.Article in journal (Refereed) Published
In the present work, we study the bonding of 4-tert-butyl pyridine (4TBP) to the TiO2(110) surface using photoelectron spectroscopy (PES) and density functional theory (DFT) calculations. The results show that at low coverage, 4TBP adsorbs preferentially on oxygen vacancies. The calculated adsorption energy at the vacancies is 120 kJ/mol larger than that oil the five-fold-coordinated Ti4+ sites located in the rows on the TiO2 surface. The vacancy is "healed" by 4TBP, and the related gap state is strongly reduced through charge transfer into empty pi* orbitals on the pyridine ring. This leads to a change in surface band bending by 0.2 eV toward lower binding energies. The band bending does not change with further 4TBP deposition when saturating the surface to monolayer coverage, where the TiO2 surface is effectively protected against further adsorption by the dense 4TBP layer.
Place, publisher, year, edition, pages
2010. Vol. 114, no 5, 2315-2320 p.
sensitized solar-cells, rutile 110 surface, nanocrystalline tio2, electronic-structure, oxygen vacancies, charge-transfer, adsorption, stm, molecules, defects
Physical Chemistry Materials Engineering
IdentifiersURN: urn:nbn:se:kth:diva-19179DOI: 10.1021/jp911038rISI: 000274269700047ScopusID: 2-s2.0-77249086226OAI: oai:DiVA.org:kth-19179DiVA: diva2:337226
FunderSwedish Research Council
QC 201101242010-08-052010-08-052013-12-03Bibliographically approved