Sol-gel films doped with semiconductor nanocrystals for optical applications

Sol-gel films doped with MeS (Me=Cd or Pb) nanocrystals or with MxOy (M=Ni or Co) nanocrystals have been fabricated. Two different strategies were used: for the sulfides a colloidal doping sol was prepared at room temperature and then mixed with the matrix sol. For the oxides a bifunctional ligand was used, bearing either an amine group capable of coordinating the M ions and hydrolysable siloxane groups for anchoring the metal complex moiety to the silicate matrix. In this case the oxide nanocrystals precipitate at 500°C. Films containing MeS nanocrystals showed both non-linear and active optical properties. Nanocomposite films doped with MxOy showed optical gas sensing properties.