Synthesis and characterization of nano honeycomb TiO2 electrodes

Various researches to enhance the light harvesting efficiency of dye-sensitized TiO₂ solar cells have been conducted, including on the possibility of applying inverse opal structure into the solar cells (Wijnhoven and Vos, 1998). In this study, a simple fabrication method for inverse opal TiO₂ is presented. The template used is a self-organizing material, such as polystyrene latex (diameter 309 nm). The latex is dried from its colloid with slow evaporation to form an artificial opal matrix. The voids in the matrix are filled with nanosized TiO₂ particles. Several drops of 2% TiCl₄ in methanol is put into the latex matrix, hydrolyzed and heated at 80°C after each drop. Finally, calcination of the original latex matrix and the annealing of TiO₂ were conducted at 450°C. Two kinds of the electrodes are prepared by varying the heat treatment times at 80°C to 10 and 30 minutes. The resulting samples have an anatase structure, verified using XRD. The resulting honeycomb structure after calcinations was observed using SEM.