Photocatalytic and conductive MWCNT/TiO2 nanocomposite thin films.

A conductive and photocatalytic nanocomposite thin film comprising multiwalled carbon nanotubes (MWCNTs) and TiO2 nanoparticles is fabricated based on layer-by-layer (LbL) assembly in a nonpolar solvent, toluene. An amphiphilic surfactant, aerosol OT (AOT), is used to impart opposite surface charge onto MWCNTs and TiO2 in toluene. Our fabrication technique enables the incorporation of unoxidized MWCNTs into the nanocomposite thin films, and at the same time, provides a versatile method of fabricating conformal thin films over a large area. The physicochemical properties of MWCNT/TiO2 nanocomposite thin films, including composition and photocatalytic activity, can be varied by changing the concentration of AOT during assembly. The electrical properties of the nanocomposite film, specifically its sheet resistance and conductivity, can also be tuned through changing the assembly conditions. In addition, we demonstrate that the incorporation of MWCNTs within our films leads to a significant enhancement of the photocatalytic activity of TiO2. The conductivity and enhanced photocatalytic activity of MWCNT/TiO2 thin films make them promising for the generation of highly efficient dye-sensitized solar cells (DSSCs).