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Abstract: Here, we report synthesis of star shape gold nanoparticles using seed mediated growth process. Ag+ ions have been used to catalyze the anisotropic growth of gold particles in the growth solution. Star like gold nanoparticles are characterized using UV–vis and TEM study. Excitation of localized surface plasmon of star shaped gold nanoparticles by the visible radiation results broad and intense localized surface plasmon resonance excitation band. Emission spectra of nanostars upon excitation at 230nm and 480nm has been explained due to localized plasmon at the edge of star like particle and the longitudinal mode of these anisotropically grown gold nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: A method for the size-controlled synthesis of silver nanoparticles is proposed and described. Synthesis is based on the reduction of AgNO3 in aqueous SDS solution by hydrogen. These nanoparticles are poly-disperse in size and shape and their dimensions can be easily controlled in the range of 20 to 60 nm by varying the concentration of AgNO3. Silver nanoparticles are analyzed using transmission electron microscope (TEM) and UV–vis spectroscopic technique. A comparison between the experimentally observed UV–vis spectra and the simulated one obtained from the modified Mie''s theory, are made to understand the nature of shift of the SPR band. [Copyright &y& Elsevier]