Charge-transfer peculiarities in mesoporous BiVO4 surfaces with anchored indoline dyes

Abstract : Mesoporous thin films of bismuth vanadate were synthesized by sol–gel method with defined deposition parameters and annealing treatments leading to nano-textured surfaces. The stabilization of monoclinic BiVO4 structure was demonstrated by structural investigations and nano-islands morphology of the films illustrated by Atomic Force Microscopy (AFM) studies. Indoline dyes (D149) were used to sensitize the film surfaces able to show photoinduced charge transfer on the hybrid surfaces using Kelvin force microscopy (KFM). The distributions of the surface electrical potentials were compared as function of the surface texture and the sensitization by dyes. A model of the band alignment in hybrid systems was proposed to account for the observed charge transfer. The photocatalytic activity of the hybrid films was also investigated and discussed.