Nonlinear optical properties of semiconductor quantum dots and organic molecules in glasses prepared by the sol-gel method

Nonlinear behavior of glasses and especially thin films prepared by the sol-gel method make these materials an interesting class for optoelectronic devices especially when connected with their wave guide properties. From theoretical point of view these materials provided models for three-dimensional quantum confinement and allow identification of the energy of the excited states. These energy states of the quantum dots are positioned between the discrete energy levels of the atoms or bands of molecules and the broad band of the condensed phase. We describe the preparation of glasses doped by fluorescein, acridine and methyl-orange and discuss the origin of their nonlinear properties. Preparation of glass films doped by CdS and CuCl quantum dots are also presented and their properties analyzed. The relation between the energies of the electronic states and size of the particles are discussed.