Microwave monitoring of silver nanoparticle sintering for surface-enhanced Raman scattering substrates

One of the most widely used methods for surface-enhanced Raman scattering (SERS) employs silver or gold nanoparticles either in colloidal suspension or in the dry-drop form. In such substrates the SERS amplification factors depend critically on the interparticle distances. Here, we report that microwave absorption as a function of temperature in dry-drop substrates can be used as a probe to demarcate temperature regions for thermal annealing to produce SERS substrates with very high amplification factors. Copyright (c) 2011 John Wiley & Sons, Ltd.