Organic-inorganic solids by sol-gel processing: optical applications

We have developed pure inorganic and hybrid organic-inorganic solids by sol-gel processing of silicon alkoxides. `Dense' gels are obtained at room temperature, in any desired shape, including thin films, and we are able to trap organic molecules or clusters. Gels can be polished and exhibit optical transmission in the visible range similar to that of high-temperature silica glasses. Concerning `gel-molecule' and `gel-nanocrystal' composites, the diversity of the organofunctional alkoxide precursors allows us to modify the optical properties by changing the nature and the strength of chemical and electronic interactions between the optically active guest system and the solid host matrix.