A. Vats, R. Shende, J. Swiatkiewicz, J. Puszynski
The DSSC is a low-cost device as compared with the conventional ‘p-n’ junction devices. This device utilizes about 5 m thick film of TiO2 nanocrystals to form a ‘bulk’ junction with a large surface area at the semiconductor/electrolyte interface that provides sufficient anchoring sites for dye sensitizers to yield effective energy conversion. This research has been focused on the synthesis of a mesoporous thin-film of TiO2 for its application in DSSC devices using a sol-gel method. In this, a sol-solution containing a non-ionic surfactant, Ti-alkoxide precursor, and an acid catalyst was spin-coated on conductive glass substrates. Removal of the surfactant template was accomplished by solvent leaching and calcination at 400-450oC. The X-ray diffraction analysis of the films indicated presence of the cubic anatase phase and TEM images showed mesopores in the range of 4-8 nm. The surface roughness of the films was about 2 nm over an area of 600 nm2. In another synthesis method, we are investigating deposition of TiO2 film by infusion and selective condensation of Ti-precursor in surfactant films by the supercritical CO2. As an extension of this method, we are exploring the atomic layer deposition of mesoporous TiO2 film. For these films, less dye aggregation, higher surface coverage, and effective energy conversion are expected.