Core-shell-typed Ag@SiO2 Nanoparticles as Solar Selective Coating Materials

Abstract

Silver (Ag) nanoparticles with typical diameter of about 50 nm have been prepared via a polyol process. The as-prepared Ag nanoparticles are well crystallized and exhibit a characteristic surface plasmon resonance (SPR) band centered at ~423 nm. The SPR band shows a strong dependence on the sizes of Ag nanoparticles and the types of the dielectric medium. Core–shell-typed Ag@SiO2 nanoparticles have also been prepared by depositing a thin layer (~25 nm) of silica on Ag nanoparticles. The core–shell-typed Ag@SiO2 nanoparticles show similar optical behaviors (absorption, transmission, and reflection) but enhanced stability compared to those of the Ag nanoparticles, indicating that the core–shell-typed Ag@SiO2 nanoparticles may be used as solar selective coating materials for architectural window applications.