Direct printing of gold nanospheres from colloidal solutions by pyroelectrohydrodynamic jet allows hypersensitive SERS sensing

Pyro-electrohydrodynamic jet printing (p-jet) has been used to fabricate a nanostructured plasmonic sensor forSERS spectroscopy. The p-jet approach allowed us to have an assembly of nanoparticles with suitable geometryand size, which resulted in a sensing surface with intense SERS activity and a rather homogeneous response.Raman imaging measurements highlighted strong Enhancement Factors across the sensing area, exceeding thoseof the pristine colloidal solution by almost two orders of magnitude. The intense plasmonic effect was furtherdemonstrated by the spectroscopic recognition of a metal-catalyzed dimerization process triggered to completenessat the metal surface. The results presented herein demonstrate the usefulness of the proposed SERSsensor for hypersensitive molecular analysis.