Fabrication of mesoporous titania aerogel film via supercritical drying

Using a supercritical drying method, fluorine-doped tin oxide (FTO) glass was coated with a mesoporous titania aerogel film prepared from titania sols with viscosity between 10 and 60 cP that had been spin coated, immersed in IPA solution, and aged at least 3 weeks. Mesoporous titania aerogel film has an anatase structure, and an average porosity of 76%. It is hydrophilic, and its mechanical strength is improved by heat treatment at over 400 °C for 2 h. After heat treatment, the film retains its anatase structure and has a porosity of 68%. Dye-sensitized solar cells were fabricated using these mesoporous titania aerogel films. The thickness of the film was about 1 μm and the highest photo conversion efficiency, obtained when the film was heat treated at 450 °C for 2 h, was 3.71%.