Hydrothermally tailored anatase TiO₂ nanoplates with exposed {1 1 1} facets for highly efficient dye-sensitized solar cells

TiO₂ nanostructures with unique morphology, pseudo-square shaped, non-aggregated and exposed facets are of great interest in several fields including photovoltaic applications. In particular, 1-D TiO₂ nanorod or 2-D TiO₂ nanosheet based dye-sensitized solar cells (DSSCs) often show promising photovoltaic performance due to their 1-D and 2-D morphologies, respectively. Therefore, exploring TiO₂ with new nanostructure is essential. In this work, we report the synthesis of non-aggregated anatase TiO₂ nanoplates with {1 1 1} facets from TiOF₂ crystals by two-step hydrothermal process. The prepared TiO₂ nanoplates were employed as a supplementary light scattering layer in the photoelectrode, which resulted in 10% improvement in the photovoltaic performance of DSSC in comparison with the photoelectrode without TiO₂ scattering layer. Such improvements were attributed to the enhancement in light scattering due to the pseudo-square shaped 2-D plate-like morphology, higher dye loading, increase in electron lifetime and the decrease in electron recombination, which were examined by photovoltaic characterization, impedance analysis, UV–vis diffuse reflectance and absorbance spectra.