Influence of hydrodynamic conditions on growth and geometry of anodic TiO2nanotubes and their use towards optimized DSSCs

Abstract

In the present work we grow anodic TiO₂ nanotube layers under defined hydrodynamic conditions using a rotating Ti anode. We show that hydrodynamic control can be beneficially used to achieve two main effects. First, under conditions where tube growth is controlled by diffusion (for low concentration of fluoride ions in the electrolyte), growth can significantly be accelerated (or even be enabled) by increasing flow rates in the electrolyte. Second, ill-defined nanotube top morphologies can be avoided – this is particularly important in view of designing optimum tube geometries for the use of TiO₂ nanotube layers in photoelectrochemical applications such as DSSCs.