Multifunctional organic-inorganic nanocomposites for photonics

Multifunctional organic-inorganic nanocomposites are of considerable interest in photonics, optoelectronics, and biophotonics. This paper will focus on two topics. In the first part of the paper, we will focus on semiconductor nanocluster sensitized photoconductivity and photorefractivity. The results of photorefractivity studies in newly developed polymer composite PVK: TCP: CdS: NPP are presented. The composite contains charge transporting polymeric matrix of poly [N-vinylcarbazole] (PVK), thiocresol capped CdS photosensitizing nanoclusters, and second-order nonlinear optically active chromophore N-(4-nitrophenyl)-L-prolinol (NPP). Efficient plasticization of the host polymeric matrix was achieved with tricresyl phosphate (TCP). The electro-optic modulation, degenerate four-wave mixing (DFWM) diffraction efficiency and two-beam coupling properties of photorefraction were studied. In the second part of the paper, we investigate surface enhanced fluorescence in a silica matrix using dye in close association with silver nanoclusters. To optimize the photonic functions of 4-[N-(2-hydroxyethyl)-N-(methyl) amino phenyl]-4'-(6-hydroxyhexyl sulfonyl) stilbene (APSS) we have utilized the concept of plasmon enhancement, where resonance interaction with nanosize metal clusters enhances the various optical properties. Novel sol-gel processing has produced composites containing APSS and silver nanoclusters. The energy transfer between the plasmon resonance of the silver nanocluster and the excited state of APSS has been demonstrated.