Anatase TiO2 hollow spheres with small dimension fabricated via a simple preparation method for dye-sensitized solar cells with an ionic liquid electrolyte

The anatase TiO 2 hollow spheres with a diameter of approximately 250   nm were synthesized by a chemical template method. Compared to conventional P25 nanocrystalline particles, the TiO 2 hollow structured materials not only have a low density, high specific surface areas, and hierarchically porous structures but also exhibit high light-scattering efficiency and fast motion of the charge carriers. A photoelectrode consisting of TiO 2 hollow spheres for use in dye-sensitized solar cells (DSSCs) is prepared, and the nanostructure and the performance of DSSCs with an ionic liquid electrolyte are investigated. Improved performance of the DSSCs (Jsc   =   8.0   mA   cm −2 , Voc   =   0.732   V, FF   =   65%, and η   =   3.79%) is obtained compared with the P25 TiO 2 nanocrystalline DSSCs (Jsc   =   7.25   mA   cm −2 , Voc   =   0.702   V, FF   =   59%, η   =   2.96%, and measured at 100   mW   cm −2 , AM 1.5   G). The improved performance is primarily due to the enhanced light scattering by the TiO 2 hollow spheres and the highly porous structure of the hollow sphere electrode, allowing the highly viscous non-volatile electrolytes to thoroughly penetrate the electrode. The results show that the structure of the TiO 2 hollow sphere photoelectrode can greatly improve the performance of the DSSCs with non-volatile electrolytes.