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Present investigation demonstrates a very simple seed-mediated route for the synthesis of silver nanorods in aqueous solution. Central to the concept of seed-mediated growth of nanoparticles is that small nanoparticle seeds serve as nucleation centres to grow nanoparticles to a desired size and shape. Hydroxypropyl methyl cellulose (HPMC) has been used as soft template for one-dimensional growth of silver particles. Morphological, structural and spectral changes that are associated with the seed-mediated growth of the nanoparticles in presence of HPMC are characterized using UV-vis and HR-TEM spectroscopic study. Simulation of UV-vis extinction spectra of our synthesized silver nanorods has been carried out using discrete dipole approximation methodology. The broad red-shifted longitudinal extinction band of green-coloured silver sol has been explained, due to the presence of silver nanorods of different aspect ratios. [ABSTRACT FROM AUTHOR]

Abstract: Solution-phase synthesis of nanometer-sized silver particles is reported by sodium borohydride reduction of AgNO3. Two isomeric dicarboxylates (sodium maleate and sodium fumarate) have been used as stabilizing agents. The dicarboxylate-stabilized silver nanoparticles are characterized by UV–vis spectroscopy, high-resolution transmission electron microscopy (HR-TEM) and fourier transform infrared (FT-IR) spectroscopy. A qualitative comparison is made between the UV–vis spectral characteristic of the SPR band and the simulated curve obtained from modified Mie''s theory. Silver nanoparticles prepared using these two isomeric dicarboxylates show intense fluorescence in the visible region. DFT with hybrid functional (B3LYP)-based frequency (IR) calculation of both the dicarboxylates and the respective nanoparticles are in good agreement with the experimental IR frequency. On the basis of this calculation a model has been proposed for the stabilization of silver nanoparticles by these two isomeric dicarboxylate anions. [Copyright &y& Elsevier]

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]