We modified the Controlled-Double-Jet-Precipitation (CDJP) method by injecting the silver salt and reducing agent into the silica-dispersed solution through two syringes. By changing the injected volume and rate, we obtained silica/silver core/shell particles with different sizes. As a new attempt, diethanolamine (DEA) was adopted as both the reducing agent and surface functionalization agent for the silica sphere surfaces. The mechanism is discussed in detail. TEM images showed that the silica surface was coated uniformly with silver nanoparticles and the samples were also uniforrn and low in polydispersity. The CDJP was adopted here to fine tune the coating process. The silica-silver particles could be prepared in several hours with low cost and in large quantities. Characterizations,...[ Read more ]

We modified the Controlled-Double-Jet-Precipitation (CDJP) method by injecting the silver salt and reducing agent into the silica-dispersed solution through two syringes. By changing the injected volume and rate, we obtained silica/silver core/shell particles with different sizes. As a new attempt, diethanolamine (DEA) was adopted as both the reducing agent and surface functionalization agent for the silica sphere surfaces. The mechanism is discussed in detail. TEM images showed that the silica surface was coated uniformly with silver nanoparticles and the samples were also uniforrn and low in polydispersity. The CDJP was adopted here to fine tune the coating process. The silica-silver particles could be prepared in several hours with low cost and in large quantities. Characterizations, such as TEM, SEM, EDX, XRD, FT-IR, and UV-vis, were also conducted. The surface silver shell was made mainly of amorphous silver nanoparticles. The coating was compact and displayed a multi-pole plasmon resonance pattern. Further work on the silver coated metallodielectric spheres was carried out, such as preparation of silver hollow spheres and fabrication of colloidal crystals.