Double light-scattering layer film based on TiO2 hollow spheres and TiO2 nanosheets: Improved efficiency in dye-sensitized solar cells

► A novel TiO2 double-layer composite film is successfully fabricated. ► The TiO2-hollow spheres overlayer exhibited intense scattering ability. ► The TiO2-nanosheets underlayer can enlarge the contact area and increase the contact points between TiO2 photoelectrode and FTO glass. ► TiO2-double light-scattering layer film cells have the maximum conversion efficiency.