Structural and optical investigations of SiO2-CdS core-shell particles.

Cadmium sulfide nanoparticles (∼5 nm), chemically capped using thioglycerol molecules, have been anchored onto silica particles (∼80 nm) functionalized with 3-aminopropyltrimethoxysilane. Transmission electron microscopy clearly showed that at a low concentration of cadmium sulfide, nanoparticles were discretely and more or less uniformly attached onto the silica particles. At a high concentration of cadmium sulfide nanoparticles, an approximately 6-nm-thick compact shell of cadmium sulfide was formed on the silica particles. In both cases the nanocrystalline nature of cadmium sulfide particles was preserved, as is evident from X-ray diffraction and optical absorption spectra.