Fabrication of Scattering Spheres-Embedding Three-Dimensional Ordered Macroporous Titania and Application in Dye-Sensitized Photoanode

Scattering spheres-embedding three-dimensional ordered macroporous (3DOM) titania(TiO2) was fabricated, by the route of colloidal spheres self-assembly, infiltration and template removal. The procedures of 3DOM structure preparation were characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD). The silica@PMMA core-shell spheres were prepared and self-assembled into colloidal crystal template. Solid material was deposited in the colloidal crystal template by spin-coating of titania nanoparticle dispersions. Subsequently, the samples were heated to 400 °C to form anatase TiO2and to remove the polymer of template, which resulted in macroporous structure with a silica sphere in each lattice pore. The conventional TiO2film, 3DOM TiO2photoanodes were also fabricated. It was found that SiO2-embedding 3DOM photoanode has the higher photocurrent efficiency than both of TiO2 film and 3DOM, because there are scattering spheres in its lattice pores which enhance the light scattering and improve the light harvest of the dye.