PHOTOSENSITIZATION OF NANOCRYSTALLINE TIO2 THIN-FILMS BY A POLYIMIDE BEARING PENDENT SUBSTITUTED-RU(BPY)(3)(+2) GROUPS

Under visible illumination, a thin film of nanocrystalline TiO2, coate d with an adsorbed substituted-Ru(bpy)(3)(+2)-labeled polyimide 1 prod uces a sensitized photocurrent when spin-coated on a conductive ITO su pport. The magnitude of the observed anodic photocurrent defines the e fficiency of charge injection from the adsorbed dye to the nanoparticl e and of interparticulate electron hopping to the conductive support. Power characteristics and photocatalytic activity of the sensitized hi m have been investigated. Laser flash photolysis at different applied potentials produces transient absorption spectra that have been analyz ed as multicomponent charge injections. Lifetime measurements permit a characterization of the efficiency of electron migration across the s emiconductor film. The polymeric dye is also shown to be an effective photosensitizer in inducing the catalytic oxidative decomposition of m ethylene blue. (C) 1998 Elsevier Science S.A. All rights reserved.