The controllable synthesis of chain-like TiO₂ networks with multiwalled carbon nanotubes as templates and its application for dye-sensitized solar cells

The anatase TiO₂ nanostructure with large surface area and fast photoelectron-transfer channel can be an ideal structure for the fabrication of dye-sensitized solar cell (DSSC) photoelectrode. The high surface area can provide more sites for dye adsorption, while fast photoelectron-transfer channel can enhance the photogenerated electron transfer to complete the circuit. In this work, the chain-like TiO₂ networks with large surface area and long particulate connection structure have been obtained through a facile wet-chemical method using multiwalled carbon nanotubes as templates. The diameter of TiO₂ chain is ca. 15 nm and its interconnection degree can be controlled by adjusting the amount of reactive reagent. DSSC based with dense interconnection chain-like TiO₂ network photoelectrode exhibits higher conversion efficiency (6.58 %), which is higher than that of DSSC based on photoelectrode with sparse interconnection chain-like TiO₂ or conventional P25 nanoparticles under the same conditions. This is because it has higher surface area and the fastest interfacial charge transfer, which is proved by N₂ sorption isotherms and electrochemical impedance spectra.