The Study Of The Effect Of Pre-Pattern On The Growth Of Titanium Oxide Nanotube

As the current hot research field, nanotechnology and nanomaterial has drawn extensive attentions, the reason is that materials with nano scale have extraordinary optical, biological, catalytic characteristics, etc. Among the numerous materials with nanostructures, TiO₂ has drawn extra attentions because of its properties such as nontoxic, stable, easy to fabricate and high resistance to corrosion, etc. TiO₂ nanotube has been widely used in science research fields such as photocatalysis and thin film solar cell. In the dye sensitized solar cell (DSSC), TiO₂ nanotubes act as the holder of the dyes and the conductor of the electrons, on one hand the TiO₂ nanotubes have to be with high surface-to-volume ratio in order to hold more sensitized dyes which can convert the solar energy into electricity, on the other hand the TiO₂ nanotubes have to be regular and uniform in order to prevent the unnecessary recombination of the electron-hole pairs during the transfer process due to the complexity and irregular of the transfer route. So it is of great importance to fabricate TiO₂ nanotubes with long range order and regular structure. Of the mainstream, anodization method is a way to fabricate TiO₂ nanotubes. Based on lots of experiments, this paper proposed two methods to study the effects of the pre-pattern on the growth process of the TiO₂ nanotubes, one is named pre-pattern using photolithography, the other is named pre-pattern using mechanical-etching. The pre-pattern using photolithography is a method which firstly spined photoresist on the clean Ti sheet, then the Ti sheet went through exposure, developing and fixing successively to form a photoresist film with micro-nano structure on Ti sheet's surface. After that, this pre-patterned Ti sheet was put into the anodization device and went through electrochemical corrosion to form TiO₂ nanotubes. The main purpose of the photolithography pre-pattern is to guide the growth of the TiO₂ nanotubes during the anodization process by the regular micro-nano structure of the photoresist. Mechanical-etching as the pre-pattern is a method which used the grating ruling engine to etch the surface of the polished Ti sheet to form a series of grooves with small spacial intervals. Then the Ti sheet was anodized with the traditional method to grow the TiO₂ nanotubes. We found that with this kind of pre-pattern, the TiO₂ nanotubes grew faster with higher surface-to-volume ratio and a"V shaped"new structure was formed which expanded the distribution dimensions of the nanotubes.