Microstructure, optical and optoelectrical properties of mesoporous nc-TiO 2 films by hydrolysis-limited sol–gel process with different inhibitors

Abstract

Mesoporous nanocrystalline titania (nc-TiO 2) 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 N 2 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-TiO 2 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 (S BET) varies from 34 to 176 m 2/g, and crystal size is from 5.6 to 38.2 nm. The mesoporous photoanode with high S BET and large crystalline grains may be responsible for increasing conversion efficiency of the DSSCs.