Patent ID: 6730282
Filing Date: 2004-05-04
Classification: C09K

Abstract:
Sol-gel process for the manufacture of nanocomposite materials photoluminescent at ambient temperature comprising the following steps:preparing an aqueous or hydroalcoholic mixture containing a silicon alkoxide, an additional component A, and an acidic catalyst, wherein the molar ratio between water molecules and silicon atoms is equal to or higher than 4; causing the mixture to gel obtaining a wet gel; causing said wet gel to dry; and densify the thus obtained dry gel by means of a thermal treatment having a maximum temperature comprised between 1200Â° C. and 1400Â° C.; characterized in that:the additional component A is a dialkyldialkoxysilane, R2â€”Siâ€”(ORâ€²)2, or an alkyltrialkoxysilane, Râ€”Siâ€”(ORâ€²)3, wherein R and Râ€² radicals are not aromatic; and in the range from 300 to 800Â° C. the thermal treatment is carried out under an atmosphere made up of pure HCl or a mixture containing at least 5% by volume of HCl in an inert gas, said atmosphere being anhydrous and not containing oxygen.