Preparation Of Core-shell Structure Substrates And Their Raman Scattering Characteristics

SiO2 nanoparticles with different size were prepared by St?ber method under optimizated condictions. Surface modification of Si O2 nanoparticles were performed using esterification reaction. TEM measurement results showed that all nanoparticles were spherical and uniform in size.Monolayer films, which was composed of different-sized Si O2 nanoparticles, were fabricated with Langmuir-Blodgett(LB) deposition method. Si O2/Au core shell substructure with different core size and same shell thickness were successfully obtained via sputtering Au ions upon the monolayer films of silica nanoparticles. Si O2/Au、Si O2/Ag、Si O2/Cu substructure with same core size and shell thickness were fabricated the same way. The Scanning electron microscope(SEM) and UV visible transmission spectroscopy showed that the nanoparticles of substrates were closely arranged, and the substrates presented excellent surface plasma resonance effect.Surface enhance Raman scattering(SERS) of obtained substrates were studied with methylene blue(MB) as probe molecule. All substrates displayed good SERS effect, as shown in the results, Si O2/Ag substrates had a higher enhancement factor than substrates of Si O2/Au, Si O2/Cu substrates possessed weakest reinforcing ability. Further studies showed that Si O2/Au substrates also took on excellent stability and uniformity.