Tuning Anatase-Rutile Phase Transition Temperature: TiO/SiO Nanoparticles Applied in Dye-Sensitized Solar Cells

Abstract

TiOSiO nanoparticles with 3, 5, and 10 molar percent of silica, were synthesized by hydrothermal method and characterized by SEM, TEM, N adsorption-desorption isotherms, X-ray diffraction, and Raman and UV-Vis spectroscopy. While pristine TiO thermally treated at 500°C presents a surface area of 36 m g (±10 m g), TiO/SiO containing 3, 5, and 10 molar percent of silica present surface areas of 93, 124, and 150 m g (±10 m g), respectively. SiO is found to form very small amorphous domains well dispersed in the TiO matrix. X-ray diffraction and Raman spectroscopy data show that anatase-to-rutile phase transition temperature is delayed by the presence of SiO, enabling single-anatase phase photoanodes for DSSCs. According to the I×V measurements, photoanodes with 3% of SiO result in improved efficiency, which is mainly related to increased surface area and dye loading. In addition, the results suggest a gain in photocurrent related to the passivation of defects by SiO.