Abstract

A new facile strategy for preparation of mesoporous anatase-TiO2 films by a combination of sol-gel and evaporation-induced self-assembly (EISA) processes aided by tri-block Pluronic F127 is reported. Two major parameters, sol preparation and EISA processing parameters, are identified for preparation of mesoporous crack-free films with desired thickness. The mesoporous crack-free films with thickness of 650 nm can be obtained with low water: precursor molar ratio (e.g., 2.5:1) under aging in 10 % relative humidity for 72 h at the low temperature of 5 degrees C. Although template: precursor molar ratio and annealing temperature show little influence on preparation of crack-free films the optimum values are determined 0.005: 1 and 350 degrees C, respectively. Reducing the aging temperature down to 5 degrees C not only hinders the anatase-to-rutile phase transformation but also retards crystal growth. Furthermore, Brunauer-Emmett-Teller and Barrett-Joyner-Helenda results show that the isotherm corresponding to synthesized powders represents a combination of types II and IV corresponding to mesoporous materials with average pore size in the range 5.8-8.8 nm and BET surface area of 72-99 m(2)/g. UV-Vis absorption spectrum of prepared mesoporous TiO2 film displays a blue shift relative to that of bulk TiO2 due to the quantum size effect. The mesoporous TiO2 film prepared under optimized conditions has good microstructural and optical properties for dye-sensitized solar cell (DSSC) applications. The DSSC made of optimized mesoporous TiO2 film shows cell efficiency and short circuit current density of 6.31 % 15.23 mA/cm(2), respectively.