title: Chemical control of photoexcited states in titanate nanostructures.
abstract: The photoelectronic properties of layered titanate nanostructures can be adjusted by changing the nature and bonding state of ions in the interlayer region. We studied the optical properties of titanate nanowires and nanotubes obtained after soft-chemical treatment of TiO2 anatase powders. A photoluminescence emission process originating from exciton states trapped in [TiO6] units was observed in anatase TiO2 and, with significantly enhanced intensity, in nanowires made of titanate nanosheets. On the basis of a correlation between emission intensity and the concentration of intercalated alkali ions, we conclude that protonation of the [TiO6] octahedra that constitute the titanate sheet structure suppresses radiative deactivation of trapped excitons and can be reversed by ion exchange.
authors.affiliation: Institute of Materials Chemistry, Vienna University of Technology, Veterinärplatz 1/GA, A-1210 Vienna, Austria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Riss
authors.forename: Thomas
authors.initials: T
authors.lastname: Berger
authors.forename: Hinrich
authors.initials: H
authors.lastname: Grothe
authors.forename: Johannes
authors.initials: J
authors.lastname: Bernardi
authors.forename: Oliver
authors.initials: O
authors.lastname: Diwald
authors.forename: Erich
authors.initials: E
authors.lastname: Knözinger