Nanostructured thin films of C-60-aniline dyad clusters: Electrodeposition, charge separation, and photoelectrochemistry

Clusters of C-60 - aniline dyads are deposited as thin films on nanostructu red SnO2 electrodes under the influence of an electric field. At low applie d DC voltage (<5 V) the clusters in toluene/acetonitrile (1:3) mixed solven t grow in size (from 160 nm to <similar to>200 nm in diameter) while at hig her voltages (>50 V) they are deposited on the electrode surface as thin fi lms. The C-60 - aniline dyad cluster films when cast on nanostructured SnO2 films are photoelectrochemically active and generate photocurrent under vi sible light excitation. These nanostructured fullerene films are capable of delivering relatively large photocurrents (upto similar to0.2 mA cm(-2), p hotoconversion efficiency of 3-4%) when employed as photoanodes in photoele ctrochemical cells Both luminescence and transient absorption studies confi rm the formation of charge transfer product (C-60 anion) following UV/Vis e xcitation of these films, Photo-induced charge separation in these dyad clu sters is followed by the electron injection from C-60-anion moiety into the SnO2 nanocrystalIites. The oxidized counterpart is reduced by the redox co uple present in the electrolyte, thus regenerating the dyad clusters. The f easibility of casting high surface area thin fullerene films on electrode s urfaces has opened up new avenues to utilize dyad molecules of sensitizer b ridge donor type in light energy conversion devices, such as solar cells.