Highly connected hierarchical textured TiO2 spheres as photoanodes for dye-sensitized solar cells

We present a new type of microstructured TiO2 sea urchin-like assembly, composed of high aspect-ratio nanosheets. We also demonstrate the applicability of these structures as photoanodes in dye-sensitized solar cells, with 9.0% conversion efficiency realized, a considerable improvement over the commercial Dyesol paste (8.2%) under the same conditions. We reveal that this new TiO2 nanostructure is beneficial to enhanced dye loading and efficient light scattering. In particular, the interpenetrating individual sheets of the spheres result in more intimate interparticle connections and provide efficient electron transfer pathways.