Research on refractive index sensing properties of Ag@SiO2 composite nanoparticle films
Due to their remarkable surface plasmonic properties,silver nanoparticles can be used as a key material for refractive index sensing,and have widespread applications in fields such as chemical catalysis,information sensing,medical biology,and new energy sources.However,uncoated pure silver nanoparticles are easily oxidized in complex media environments,the long-term stability of refractive index sensing cannot be maintained.In this paper,an Ag@SiO2 composite nanoparticle film for refractive index sensing was proposed.The structure unit consists of an island-silver nanoparticle and a silica shell was attached to the surface of the silver particles.In this paper,the finite-difference time-domain(FDTD)method was used to simulate and calculate the spectral characteristics and refractive index sensing performance of Ag@SiO2 composite nanoparticles with varying coating thicknesses.The results indicate that the resonance peak of the Ag@SiO2 nanoparticle film strongly depends on both the thickness of the coating material and the refractive index of the surrounding medium.The refractive index sensitivity of the Ag@SiO2 nanoparticle film surpassing that of uncoated pure silver nanoparticles.The Ag@SiO2 composite nanoparticle film proposed in this study exhibits superior performance compared to island-shaped pure silver nanoparticles,holding promise as a key material for refractive index sensing with potential applications in various media environments.
localized surface plasmonrefractive index sensingnanoparticle filmfinite-difference time-domain methodextinction spectroscopy
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