UNIGE document Scientific Article
previous document  unige:25114  next document
add to browser collection
Title

Excited-state dynamics of porphyrin–naphthalenediimide–porphyrin triads

Authors
Bhosale, Sheshanath V.
Langford, Steven J.
Published in Physical Chemistry Chemical Physics. 2013, vol. 15, no. 4, p. 1177
Abstract The excited-state dynamics of two triads consisting of a naphthalenediimide (cNDI) substituted at the core by two zinc (ZnP) or free-base tetraphenylporphyrins (FbP) was investigated by ultrafast fluorescence and transient absorption spectroscopy. The electronic absorption spectra of the triads are almost the composites of those of the constituents, pointing to a weak electronic coupling and to a localization of the excitation energy on one of the porphyrins. In cyclohexane, the excited-state dynamics of the triads are essentially the same as those of the individual porphyrins, with the exception of the Soret emission of the ZnP triad, whose lifetime exhibits a more than 10 fold shortening compared to ZnP. A similarly ultrafast fluorescence decay was measured in tetrahydrofuran and benzonitrile. In these two solvents, charge separation from the excited porphyrin to the cNDI was found to take place with ~1 ps and ~25 ps time constants in the ZnP and FbP triads, respectively. The build up of the charge-separated state population in the ZnP triad is independent on the excitation wavelength, indicating that charge separation takes place from the lowest singlet excited state. Charge recombination occurs with a time constant around 8 ps in both triads, i.e. is slower than charge separation in the ZnP triad but faster in the FbP triad. These differences are rationalized in terms of the driving forces for charge separation and recombination.
Identifiers
Full text
Article (Published version) (2.8 MB) - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://xlink.rsc.org/?DOI=c2cp43595k
Structures
Research group Groupe Vauthey
Citation
(ISO format)
VILLAMAINA, Diego et al. Excited-state dynamics of porphyrin–naphthalenediimide–porphyrin triads. In: Physical Chemistry Chemical Physics, 2013, vol. 15, n° 4, p. 1177. https://archive-ouverte.unige.ch/unige:25114

249 hits

0 download

Update

Deposited on : 2013-01-08

Export document
Format :
Citation style :