Authors: L. Mercado, W. Castro, E. Vicuña, J.G. Briano, Y. Ishikawa, R. Irizarry, L. Solá and M.E. Castro
Affilation: University of Puerto Rico, United States
Pages: 439 - 442
Keywords: silver, nanoclusters, ions, kinetics, plasmon
Metallic clusters of noble metals are of tremendous technological importance due to their conduction properties, size, low reactivity and optical properties. Clusters containing as few as two and four silver atoms have been prepared in our laboratory by the reduction of the silver ion (Ag+) with OH- in basic solution. The UV absorption spectra of AgNO3 / NaOH solutions are characterized by the appearance of UV absorption peaks at 275 and 310 nm, attributed to the formation of the tetramer di-cation Ag42+ and to Ag2+ or small non metallic clusters (Agn), respectively, and at about 380 nm due to the excitation of the silver plasmon in larger clusters. The 275 and 310 nm peak areas were found to be sensitive functions of initial AgNO3 and NaOH concentrations.