Electrophoretic deposition of colloidal TiO2 nanorods towards nano-porous thin-films

Nanostructured and nano-porous thin films, offering elevated active surface, are of significant importance for a wide variety of technological applications. Here we report on the electrophoretic deposition - on a conductive substrate - of colloidal TiO2 rod-like shaped nanocrystals dispersed in an organic solvent. Colloidal synthesis allowed obtaining a careful control over the morphological properties and the crystallographic phase of nanoparticles, which resulted in rod-shaped anatase nanocrystals. Compared to spherical nanocrystal, the rod-shape offers enhanced surface/volume ratio, which limits the charge recombination. The electrophoretic deposition drives nanorods toward the immobilization on the conductive surface of the substrate, forming homogeneous nanoporous thin-films composed by densely packed nanorods. Indeed, SEM analysis endorsed that the morphology of NRs is preserved in the thinfilm. The approach reported here colloidal synthesis followed by electrophoretic deposition - could be extended to the functionalization of different surfaces with the peculiar properties inferred by the nanoparticles.