The Journal of Physical Chemistry B · 1998 · 294 citations · 13 references
Natural SciencesChemistryMaterials ScienceElectrochemistrySpectroscopySurface ScienceCharge Transfer ReactionsElectrode KineticsPhotoelectrochemical MaterialsPhotoelectrochemistrySemiconductor NanomaterialsSurface PhysicsCharge Transfer DynamicsElectron Transfer DynamicsFemtosecond SpectroscopyInfrared Absorption SpectraInfrared Absorption SpectroscopyNanocrystalline MaterialsPhotocarrier DynamicsUltrafast Carrier Dynamics
We have used femtosecond pump−probe spectroscopy to time resolve the injection of electrons into nanocrystalline TiO 2 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 TiO 2 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 TiO 2 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 Al 2 O 3 and ZrO 2 and found no indication of electron injection at probe wavelengths in the mid-IR (4.1−7.0 μm).
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Mohammad Khaja Nazeeruddin, Andreas Kay, I. Rodicio et al. · Journal of the American Chemical Society · 1993 · 6K citations · Full text