Growth of Silver Colloidal Particles Obtained by Citrate Reduction To Increase the Raman Enhancement Factor

Abstract

A method is reported for obtaining silver colloids with a large particle size. It is based on the growth of seed colloidal particles obtained by chemical reduction of silver nitrate with citrate. These colloids were characterized by means of UV−visible spectroscopy and transmission electron microscopy. The nucleation mechanism is discussed on the basis of the morphology and size of the resulting particles. Moreover, the surface-enhanced Raman scattering activity of the resulting colloids was evaluated in the near-infrared region by using 1,5-dimethylcytosine as adsorbate.