Monodisperse TiO2 hierarchical hollow spheres assembled by nanospindles for dye-sensitized solar cells†
Abstract
Monodisperse TiO2 hollow spheres assembled by nanospindles were prepared via the facile hydrothermal reaction of peroxotitanium complex precursors. Time dependent trails revealed that the shape evolution involved a one-step chemical conversion from amorphous Ti complex microspheres to anatase TiO2 hierarchical hollow spheres. Meanwhile, the sizes of the spheres could be tuned in a region of 400–1000 nm by simply adjusting the ammonia dosage of the precursor solution. Furthermore, these as-prepared hollow spheres were deposited as a scattering layer on top of the TiO2 nanocrystalline film, and a high energy conversion efficiency of 8.10% was demonstrated based on the bilayer photoanode, in contrast to a 7.29% conversion efficiency for the cell with a pure nanocrystalline photoanode.