Adsorption dynamics of the N719 dye on nanoporous titanium oxides studied by resonance Raman scattering and Fourier transform infrared spectroscopy

The adsorption dynamics of the (Bu4N)2[Ru(dcbpyH)2(NCS)2] (N719) dye on nanoporous TiO2 films were examined. Resonant Raman scattering and Fourier transform infrared absorption spectroscopy were used to study TiO2 thin films that had been sensitized in ethanol solutions for different immersion times. Our experimental results suggested that the N719 dyes were anchored to the surface of nanoporous TiO2 through bidentate chelating or bridging forms between the carboxylate groups of the N719 dyes and the TiO2 at all stage of adsorption, while the strength of intermolecular π–π interactions between adjacent bipyridine rings became stronger as the density of the adsorbed dyes increased.