Nanocomposites of titania and hybrid matrix with high refractive index

A sol-gel route for TiO2 nanocrystals (NCs) synthesis has been developed at low temperature without surfactants. Synthetic and processing parameters have been optimized to maximize particles' colloidal stability and crystallinity. The obtained TiO2 NCs can be homogeneously dispersed in a sol-gel derived organic-inorganic hybrid material, resulting in homogeneous composite films when prepared by spin coating. High refractive index films were obtained with high TiO2 NCs loading and good transparency. Furthermore, TiO2 colloidal solutions can be used for depositing porous crystalline films, whose structural evolution has been followed under different annealing treatments. Nanocrystals were characterized by UV-Vis absorption, TEM, FT-Raman, and XRD techniques, while nanocomposite and TiO2 films were analyzed by SEM, TEM, and spectroscopic ellipsometry.