Fabrication of high quality electrochemical SERS (EC-SERS) substrates using physical vapour deposition

Screen-printed electrodes (SPEs) are an efficient and inexpensive substrate for electrochemical surface-enhanced Raman spectroscopy (EC-SERS) studies. Traditionally, the working electrode of the SPE is modified with either a colloidal paste of metal nanoparticles or an electrodeposited metallic film. These methods can be time-consuming and often produce non-uniform nanostructured films. Physical vapour deposition (PVD) is presented in this work as an efficient and effective alternative method for the production of SERS-active SPEs. SPEs coated with silver thin films via PVD show consistent and strong EC-SERS enhancement for the detection of two probe molecules, 4-aminothiophenol (p-ATP) and 5-(pyridine-4-yl)-1,3,4-oxadiazole-2-thiol (PYOT). The EC-SERS signal intensity for p-ATP and PYOT had coefficients of variation of 8.2% and 5.5%, respectively. More generally, these substrates show promise for reliable enhancement of molecules spanning diverse analytical applications.