Morphology and Optical Properties of Bare and Silica Coated Hybrid Silver Nanoparticles

Owing to their wide applications in the field of optoelectronics, photonics, catalysis, and medicine; plasmonic metal nanoparticles are attaining considerable interest nowadays. The optical properties of these metal nanoparticles depend upon their size, shape, and surrounding medium. The present work studies the morphology and optical properties of bare silver nanoparticles and silica coated hybrid silver nanoparticles. Aqueous phase mediated synthesis and water-in-oil microemulsion mediated synthesis are two different wet chemical routes employed for nanosynthesis. Direct coating of silica is performed in water-in-oil microemulsion on pre-synthesized silver nanoparticles using tetraethyl orthosilicate as silica precursor. This study shows that using different wet chemical routes the size of the synthesized nanoparticles could be tuned. In addition, using reverse micelles as nanoreactors, the thickness of the silica shell around the core silver nanoparticles could be significantly controlled. Further, the optical properties of silver nanoparticles could be adjusted through the size and the surface coating.