Nanostructured Hybrid Solar Cells Based on Self-Assembled Mesoporous Titania Thin Films

Abstract

Nanocrystalline mesostructured porous titania thin films with optimized coating and thermal curing conditions have been prepared for the first time using spin-coating deposition technique. The X-ray diffraction (XRD) and the grazing incidence small-angle X-ray scattering (GI-SAXS) measurements revealed that the crystallization and diffuse sintering of amorphous TiO2 into anatase are simultaneously starting between 400 and 500 °C curing temperature, leading to a gridlike open-pore-shape transformation. The environmental ellipsometric porosimetry (EEP) measurements show that the 550 °C-cured TiO2 films exhibit a high porous volume (0.30 cm3 g-1), a large surface area (172 m2 cm-3), and a Young modulus of 1.05 GPa. All solid-state dye-sensitized solar cells (DSSC) based on nanocrystalline mesostructured TiO2 films and poly(3-octylthiophene) as hole conductor allow reproducible achievement of energy conversion efficiencies of about 0.52%. These values, obtained with thin TiO2 films (250 nm), are very promising.