Controllable Silver Plating on Silica for Surface-enhanced Raman Scattering

We proposed a facile and rapid method for preparing silica-silver core-shell(SSCS) substrates to use Ag electroless plating on SiO2@Au-seed particles.UV-Vis-NIR absorption spectrometer and SEM were employed to monitor the reaction process of the formation of Ag on the surfaces of silica beads,and the optical resonance of the substrate could shift from visible to NIR region.It has been found that surface-enhanced Raman scattering(SERS) enhancement changes with the electroless plating time and the SSCS substrate with the plating time of 90 s(90SSCS) shows the strongest SERS response under the laser excitation at 514.5 nm.Signals collected over multiple spots and substrate of rhodamine 6G(R6G) resulted in a relative standard deviation(RSD) of 9.75%.The calculated enhancement factor(EF) was approximately 105 "106.SSCS substrate exhibits high SERS performance,which is due to electromagnetic SERS enhancement with additional localization field within closely packed Ag nanoparticles decorated on the SiO2 nanoparticles.And this substrate presents tunable and broad localized surface plasmon resonance(LSPR),so this method may open a new way for SERS studies with other laser excitation.