Precursor Concentration Dependent Morphology-Tunable Hierarchical TiO2 Nanostructure for Dye Sensitized Solar Cells

Dye sensitized solar cells based on TiO2 nanorod suffers from low dye loading and poor light scattering ability, both of which obstacle the improvement of energy conversion efficiency. In this paper, we have successfully synthesized TiO2 rutile nanostructures with tunable morphology on FTO substrates with a one-step hydrothermal synthesis by changing the Ti concentration in the precursor solution. Three different photoanodes, namely, nanorod layer, nanorod layer with flower-like clusters and nanorod layer with densely packed spheres, are obtained without using any surfactants. The photoanode of nanorod layer with densely packed spheres exhibits improved dye loading and enhanced light reflection from 600-800 nm. DSSCs based on such a photoanode exhibits an energy conversion efficiency of 4.08%, achieving a nearly three-fold enhancement compared with dye sensitized solar cells based on TiO2 nanorod array.