Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Laser Applications in Environmental Metrology Photochemistry and Agriculture

A facile one-pot photochemical method has been developed to prepare different shapes of plasmonic nanomaterials and their graphene nanocomposites capped with a mixture of Oleyl Amine (O.Am) and Oleic Acid (O.Ac). Different light sources such as sunlight, UV (n = 254 nm) and halogen lamp have been used. The size, shape and morphology of the nanocrystals could be tailored by varying the light source and the exposure time. These factors strongly affect the particle shape, their self assembly into graphene surface and also the growth rate. Remarkable increase in the growth rate even at sunlight occurs upon introducing graphene oxide into the reaction mixture. The role of graphene as a catalyst and strong light absorber leads to increasing the growth rate and enhances the formation of rods, wires and more anisotropic shapes. By controlling the catalytic reduction of gold ions and the diffusion rate of gold seeds into graphene sheets, more complex structure such as snow flake gold nanostructure or self assembled regular shaped nanocrystals superlattice could be constructed on the graphene surface. The Photothermal response of these graphene based plasmonic nanomaterials has been monitored as a function of time

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