title: Ultrafast dynamics of dithienylethenes differently linked to the surface of TiO2 nanoparticles.
abstract: The photoinduced dynamics of a dithienylethene chromophore coupled to the surface of TiO(2) by either a tripodal linker or a carboxyl group was investigated with ultrafast transient absorption spectroscopy. The absence of electron transfer from the photoexcited tripodal dithienylethene chromophore demonstrates that the tripod efficiently uncouples the electronic systems of dithienylethene and TiO(2). Contrary to this situation, photoinduced electron transfer can compete with ultrafast intramolecular relaxation in the COOH-dithienylethene/TiO(2) coupled system. An electron transfer rate of 1.1 × 10(12) s(-1) can be extracted, which is considerably slower than the intramolecular relaxation rate of the dithienylethene (3.7 × 10(12) s(-1)). Consequently, the electron transfer reaction exhibits a low efficiency.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Goethe-University, Max-von-Laue-Strasse 7, D-60438 Frankfurt/Main, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Dworak
authors.forename: Marc
authors.initials: M
authors.lastname: Zastrow
authors.forename: Gehad
authors.initials: G
authors.lastname: Zeyat
authors.forename: Karola
authors.initials: K
authors.lastname: Rück-Braun
authors.forename: Josef
authors.initials: J
authors.lastname: Wachtveitl