Photoinduced electron transfer in squaraine dyes: Sensitization of large band gap semiconductors

L Blancafort, S Wilsey, M A Robb, Martin Paterson

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Squaraine dyes are known to photosensitize large band gap semiconductors via a charge-injection process from a singlet excited state. We have modeled this process with the simplest squaraine chromophore and titanium dioxide (TiO2). A TiO2-squaraine excited-state complex has been optimized with an adjacent conical intersection. This suggests that the charge injection from the excited-state squaraine into the conduction band of the semiconductor should be an ultrafast photochemical process in agreement with recent experimental results. In terms of Marcus-Hush electron transfer theory, the charge transfer for the TiO2-squaraine model occurs in the inverted region, which is a strong indication for the equivalence between electron transfer in the inverted region and radiationless decay through a sloped conical intersection.

Original languageEnglish
Pages (from-to)11431-11439
Number of pages9
JournalJournal of Physical Chemistry A
Volume106
Issue number47
DOIs
Publication statusPublished - 28 Nov 2002

Keywords

  • ORGANIC-PHOTOCHEMISTRY
  • CHARGE RECOMBINATION
  • DONOR
  • STATE
  • TIO2
  • PHOTOSENSITIZATION
  • ACCEPTOR
  • TRIPLET
  • MOLECULES
  • DYNAMICS

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