Silica−Titania-Based Organic−Inorganic Hybrid Materials for Photovoltaic Applications

Silica−titania-based organic−inorganic hybrid materials (OIHMs) containing covalently bonded organic chromophores with photosensitization ability were developed. The presence of the Ti−O−Si linkage in these OIHMs was established by infrared spectroscopy. Photocurrent and photovoltage were generated upon irradiation of these OIHM films on an indium tin oxide (ITO) glass or nanocrystalline TiO 2 surface. The photovoltaic properties depend on the relative molar fractions of silica and titania in the OIHM films. The OIHMs thus prepared can serve as anchoring matrixes for associating the chromophores with nanocrystalline TiO 2 surfaces and can be used as active layers in photovoltaic devices. Control experiments using a blending protocol suggest that covalent bonding between the chromophores and the silica−titania hybrid networks is essential to enhancing the performance of photovoltaic devices.