Dynamics of electron injection in nanocrystalline titanium dioxide films sensitized with [Ru(4,4′-dicarboxy-2,2′-bipyridine)2(NCS)2] by infrared transient absorption

Randy J. Ellingson, John B. Asbury, Sue Ferrere, Hirendra N. Ghosh, Julian R. Sprague, Tianquan Lian, Arthur J. Nozik

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Abstract

We have used femtosecond pump-probe spectroscopy to time resolve the injection of electrons into nanocrystalline TiO2 film electrodes under ambient conditions following photoexcitation of the adsorbed dye, [Ru(4,4′-dicarboxy-2,2′-bipyridine)2(NCS)2] (N3). Pumping at one of the metal-to-ligand charge-transfer absorption peaks and probing the absorption by injected electrons in the TiO2 at 1.52 μm and in the range of 4.1-7.0 μm, we have directly observed the arrival of electrons injected into the TiO2 film. Our measurements indicate an instrument-limited ∼50 fs upper limit on the electron injection time. We have compared the infrared transient absorption for noninjecting systems consisting of N3 in ethanol and N3 adsorbed to films of nanocrystalline Al2O3 and ZrO2 and found no indication of electron injection at probe wavelengths in the mid-IR (4.1-7.0 μm).

Original languageEnglish (US)
Pages (from-to)6455-6458
Number of pages4
JournalJournal of Physical Chemistry B
Volume102
Issue number34
DOIs
StatePublished - Aug 20 1998

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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