Tuning Anatase-Rutile Phase Transition Temperature: TiO_2/SiO_2 Nanoparticles Applied in Dye-Sensitized Solar Cells

摘要

TiO_2/SiO_2 nanoparticles with 3, 5, and 10 molar percent of silica, were synthesized by hydrothermal method and characterized by SEM, TEM, N_2 adsorption-desorption isotherms, X-ray diffraction, and Raman and UV-Vis spectroscopy. While pristine TiO_2 thermally treated at 500°C presents a surface area of 36 m~2 g~(-1) (±10 m~2 g~(-1_), TiO_2/SiO_2 containing 3, 5, and 10 molar percent of silica present surface areas of 93, 124, and 150 m~2 g~(-1) (±10 m~2 g~(-1)), respectively. SiO_2 is found to form very small amorphous domains well dispersed in the TiO_2 matrix. X-ray diffraction and Raman spectroscopy data show that anatase-to-rutile phase transition temperature is delayed by the presence of SiO_2, enabling single-anatase phase photoanodes for DSSCs. According to the I × V measurements, photoanodes with 3% of SiO_2 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_2.