Investigating the mechanism of uniform Ag@SiO₂ core-shell nanostructures synthesis by a one-pot sol–gel method

Abstract: Monodispersed Ag@SiO₂ core-shell structure nanoparticles (NPs) are synthesized at room temperature via a one-pot sol–gel synthesis method, and the synthesizing procedure is observed over reaction time in order to investigate the formation mechanism. Ostwald ripening of silver (Ag) core NPs and silica (SiO₂) shells during synthesis of core-shell NPs proceeds in parallel to reaction time. Uniform and stable Ag@SiO₂ core-shell NPs are formed at 48 h of reaction time. The hydrolysis rate of tetraethyl orthosilicate (TEOS) plays a critical role in the growth of Ag NPs and the final structure of Ag@SiO₂ core-shell NPs. The formation mechanisms of single-core and multicore Ag@SiO₂ core-shell NPs are discussed in relation to synchronous Ag core and SiO₂ shell growth. Optimal reaction conditions for critical parameters (water volume and TEOS and ascorbic acid concentrations) are also determined. [Figure not available: see fulltext.].