Disentangling SERS signals from two molecular species: A new evidence for the production of p,p′-dimercaptoazobenzene by catalytic coupling reaction of p-aminothiophenol on metallic nanostructures

An intriguing case has recently emerged in SERS literature regarding the correct interpretation of SERS fingerprints recorded from p-aminothiophenol molecules adsorbed on metallic surface. In this work we present an original approach to demonstrate the production of p,p′-dimercaptoazobenzene (DMAB) by catalytic coupling reaction of p-aminothiophenol (p-ATP) on the surface of polystyrene spheres decorated with gold nanoparticles. With the aim of disentangling the SERS signals from these two molecular species, our approach combines the correlation analysis of time-dependent intensity fluctuations of some representative SERS bands with their spatial mapping performed by Scanning Confocal Raman Microscopy.