Research on Chemical Intermediates

, Volume 31, Issue 7–8, pp 643–647 | Cite as

Distance dependence of heterogeneous electron transfer probed in ultra-high vacuum with femtosecond transient absorption

  • R Ernstorfer
  • S Felber
  • W Storck
  • E Galoppini
  • Q Wei
  • F Willig
Article

Electron injection from the excited singlet state of the molecular chromophore perylene into the wide-band-gap semiconductor TiO2 was investigated in ultra-high vacuum employing femtosecond transient absorption (fs-TA) spectroscopy. The chromophores were bound to saturated spacer-cum-anchor groups. The latter formed bonds on the surface of nm-structured anatase TiO2 layers. Both the latter preparation step and the fs-TA measurements were performed in a special ultra-high-vacuum chamber that can accommodate solvents. The rate constants were measured in the so-called wide band limiting case where they are controlled only by the electronic coupling strength and not by Franck–Condon factors. Measurements with different saturated anchor-cum-spacer groups revealed an exponential dependence of the rate constants on the reaction distance. The distance parameter was 0.1 nm in ultra-high-vacuum. The shortest injection time of 13 fs was measured for the carboxyl anchor group and the longest of 4 ps for the long rigid so-called tripod anchor-cum-spacer group.

ELECTRON TRANSFER FEMTOSECOND TRANSIENT ABSORPTION SPECTROSCOPY MOLECULAR DONOR SEMICONDUCTOR ULTRA-HIGH VACUUM ELECTRONIC COUPLING STRENGTH 

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Copyright information

© VSP 2005

Authors and Affiliations

  • R Ernstorfer
  • S Felber
  • W Storck
  • E Galoppini
  • Q Wei
  • F Willig

There are no affiliations available

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