Speckled SiO2@Au Core-Shell Particles as Surface Enhanced Raman Scattering Probes

Silica particles of similar to 800 nm size were functionalized using 3-amino propyl triethoxysilane molecules on which gold particles (similar to 20 nm size) were deposited. The resulting particles appeared to form speckled SiO2@Au core-shell particles. The surface roughness, along with hot spots, due to nanogaps between the gold nanoparticles was responsible for the enhancement of the Raman signal of crystal violet molecules by similar to 3.2x10(7) and by similar to 1.42x10(8) of single-wall carbon nanotubes. It has also been observed that the electromagnetic excitation near surface plasmon resonance (SPR) of core-shell particles is more effective than off resonance SPR excitation.