title: Imaging the photoinduced charge injection in CdS/TiO2nanoparticles by the sequential fluorescence mapping method.
abstract: The combination of a sensitizer and TiO2nanoparticles forming a photocatalytic material is a central issue in many fields of applied photochemistry. The charge injection of emissive sensitizers into the conduction band of the semiconductor TiO2may form a photoactive region that becomes dark, or it has a very low emission signal due to the generation of sensitizer radicals. However, by sequential coupling of a selected photoredox dye, such as resazurin, the dark region may become fluorescent at the interfaces where the charge injection has taken place due to the concomitant formation of fluorescent resorufin by cascade electron transfer. Using this strategy and a total internal reflection fluorescence microscopy (TIRFM) image, the charge injection in TiO2/CdS and SiO2/TiO2/CdS nanoparticles is investigated The method allows the charge injection efficiency of the excited CdS into TiO2to be evaluated qualitatively, explaining the differences observed for these photocatalytic materials in H2generation.
authors.affiliation: Universidade de São Paulo-Instituto de Química de São Carlos-Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Frederice
authors.forename: Diego
authors.initials: D
authors.lastname: Lencione
authors.forename: Marcelo H
authors.initials: MH
authors.lastname: Gehlen