Microstructure, optical and optoelectrical properties of mesoporous nc-TiO2 films by hydrolysis-limited sol–gel process with different inhibitors

Mesoporous nanocrystalline titania (nc-TiO2) films were synthesized by sol–gel route using poly (alkylene oxide) block copolymer as template and tetrabutyl orthotitanate as titanium source. Influence of acetylacetone (AcAc), glacial acetic acid, HCl and AcAc-HCl as inhibitors on hydrolysis/condensation reaction was investigated. The mesopore structure, crystalline phase and optical characteristics were analyzed by N2 adsorption, X-ray diffraction, transmission electron microscopy and UV–VIS–NIR spectrum. Photoaction measurements were performed on dye-sensitized solar cells (DSSCs) using the mesoporous nc-TiO2 as photoanodes. The results show that the formed films are anatase phase and mesoporous structure. Different restraining mechanisms of these inhibitors to hydrolysis/condensation process lead to different mesoporous structure whose specific surface area (SBET) varies from 34 to 176 m2/g, and crystal size is from 5.6 to 38.2 nm. The mesoporous photoanode with high SBET and large crystalline grains may be responsible for increasing conversion efficiency of the DSSCs.