Enhanced Raman Detection using Spray-On Nanoparticles/Remote Sensed Raman Spectroscopy

This report presents current research toward the use of Surface Enhaced Raman spectroscopy (SERS) for in situ analysis and remote sensing application. The Raman detection of trace amounts of explosives and other hazardous materials on surfaces was improved by ten to one thousand times (10x100x) with the addition of colloidal metallic nanoparticles to contaminated areas. In this contribution is reported the application of spraying techniques such as direct transfer and smearing, ultrasonic spraying and pneumatically assisted nebulization via an electrospray needle to prepare SERS active substrates. Silver nanoparticles colloidal suspensions were deposited on glass, silicon and stainless steel. The spectroscopic evaluation of samples was made by Raman microscopy. The distribution and morphology of silver nanoparticles and aggregates was compared for the various the deposition techniques used. Also, the use of colloids in combination with telescope assisted Raman detection showed promising results for the detection of trace levels in remote sensing systems.