Electrochemically prepared surface-enhanced Raman scattering-active silver substrates with improved stabilities.

In this work, SiO2 nanoparticles-modified surface-enhanced Raman scattering (SERS)-active silver substrates were prepared by electrochemical oxidation-reduction cycles (ORC) methods in 0.1 N HCl aqueous solutions containing 1 mM SiO2 nanoparticles to improve their thermal stabilities and anti-aging abilities in SERS performances. Then these SERS-active substrates were further modified with different contents of SiO2 nanoparticles to improve their corresponding SERS performances. Experimental results indicate that the operation temperature can be significantly raised from 125 to 175°C based on this modified SERS-active Ag substrate. Also, the aging in SERS intensity is also depressed on this modified Ag substrate due to the contribution of SiO2 nanoparticles. Moreover, the SERS enhancement capability on this modified Ag substrate is gradually raised from 25°C to a maximum at 55°C and monotonically decreased from 55 to 60°C. This is a 10°C delay as compared with the similar phenomenon observed on the unmodified Ag substrate.