Microwave-Assisted Silver Nanoparticle Film Formation for SERS Applications

Stable Ag nanoparticle (NP) films bear relevance to a large variety of applications due to their unique properties such as the surface-plasmon-resonance modes of their conduction electrons. Here a simple and fast one-step procedure is presented to obtain Ag NPs films by microwave irradiation of aqueous silver salt solutions. Ethanol, ethylene glycol, and glycerol are used as reducing agents in the absence of any other capping or stabilizing agent. Optical and morphological properties were accessed by UV–vis spectroscopy, X-ray diffraction, transmission, and scanning electron microscopy. Different substrates with different wettability and chemical nature, reactant compositions, and reaction conditions were tested to tailor the film properties. The mechanisms of particle and film formation were evaluated. The obtained surfaces represent promising SERS activity, e.g., for the model analyte riboflavin which can be detected down to the nanomolar range.