Facile fabrication of silver nanoclusters as promising surface-enhanced Raman scattering substrates

We present a simple wet chemical method to make thin film of silver nanoclusters on glass or silicon substrate. The method includes immersion of glass or silicon substrate into a saturated solution of silver nitrate in n-octanol. After 24 h, thin film of silver nanoclusters, which are micrometer-scale aggregates of silver nanoparticles with average size in the range of 80-100 nm, are formed on the substrate. The film is characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy. Potential use of the Ag nanoclusters as a surface-enhanced Raman scattering based sensing platform is demonstrated by measuring increased Raman signals from organic molecule adsorbed on the Ag nanoparticle clusters.