Controlled Synthesis of Uniform Silver Nanospheres

We describe a new route, in which the polyethylene glycol (PEG) is used both as a solvent and reducing reagent and the polymer polyvinglpyrrolidone (PVP) is used as capping agent, for the synthesis of monodisperse silver nanoparticles. Uniform nanospheres with an average diameter of 54 nm can be routinely synthesized in high yield through this approach by using a PVP/AgNO3 molar ratio of 8 at 260 degrees C. Both the reaction temperature and the PVP/AgNO3 molar ratio are crucial for the diameters and size distributions of the nanospheres.