Photochemical formation of silver nanoparticles in poly(N-vinylpyrrolidone)

Silver nanoparticles have been prepared by photoreduction of silver nitrate with 254 nm UV light in the presence of poly(N-vinylpyrrolidone). The effects of PVP concentration on the particle size, the UV-vis absorption peak and the rate of the photoreduction process were studied. The average particle size ranged from 15.2 to 22.4 nm, with the corresponding UV-vis absorption peak position at 404-418 nm in 1-0.25 wt % PVP. The rate of the photoreduction process was observed to increase with the PVP concentration. X-ray photoelectron spectroscopic studies further revealed that the polymer interacts with silver particles through the oxygen atom in the >C=O group. A negative shift of binding energy in the Ag 3d(5/2) for silver nanoparticles was observed.