Facile photochemical synthesis and characterization of highly fluorescent silver nanoparticles

Highly fluorescent silver nanoparticles (AgFNP) have been prepared by a facile photochemical method, yielding these materials in just a few minutes and with excellent long-term stability. The method makes use of photogenerated ketyl radicals that reduce Ag(+) from silver trifluoroacetate in the presence of amines. While as functional materials these AgFNP can be described as of nanometer dimensions, we believe that the luminescence arises from particle-supported small metal clusters (predominantly Ag(2)). The materials have been characterized by electron microscopy, fluorescence and absorption spectroscopy, fluorescence lifetime studies, and (19)F NMR spectroscopy. Exploratory work shows that the fluorescence from AgFNP can be efficiently quenched by paramagnetic quenchers, and these studies have been combined with electron paramagnetic resonance work.