Study of electrical field distribution and growth of gradient-arrayed TiO2 nanotubes by electrochemical anodization

In this paper, we report the simulation of electrical field distribution and growth of gradient arrayed TiO₂ nanotubes by electrochemical anodization. A rectangle electrochemical electrode configuration, in which the end of cathode (Pt wire) is perpendicularly pointed to anode surface (Ti foil), is applied in NH₄F glycol electrolyte. Electric field distribution on the surface of the titanium foil shows exponentially decreasing behavior as increasing the distance from the end of cathode. The relationship between nanotube diameter and applied voltage has been analyzed according to the images of Scanning Electron Microscopy (SEM) and simulated electrical distribution. These gradient TiO₂ nanotube arrays might be a promising nano-architecture for increasing photon-to-electrical conversion efficiency of dye sensitized solar cells (DSSC).