Ag@SiO_(2)复合纳米颗粒薄膜的折射率传感特性研究

Research on refractive index sensing properties of Ag@SiO_(2)composite nanoparticle films

银纳米颗粒具有显著的表面等离激元特性,可作为折射率传感的关键材料,广泛应用于化学催化、信息传感、医用生物和新能源等领域。然而,未包覆的纯银纳米颗粒在复杂介质环境下,无法维持折射率传感的长期稳定性。文章提出了一种用于折射率传感的Ag@SiO_(2)复合纳米颗粒薄膜,其结构单元由岛状银纳米颗粒和一层依附在银颗粒表面的二氧化硅核壳构成。利用有限时域差分法(FDTD),模拟计算了不同包覆厚度的Ag@SiO_(2)复合纳米颗粒光谱特性以及折射率传感性能。结果表明:岛状Ag@SiO_(2)纳米颗粒薄膜的共振峰强烈依赖纳米颗粒的包覆材料的厚度和周围介质的折射率。Ag@SiO_(2)复合纳米颗粒薄膜折射率灵敏度优于未包覆的纯银纳米颗粒。Ag@SiO_(2)复合纳米颗粒薄膜相对于岛状纯银纳米颗粒具有更优的指标参数,有望作为折射率传感的关键材料,应用于介质环境的检测中。

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@SiO_(2)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@SiO_(2)composite nanoparticles with varying coating thicknesses.The results indicate that the resonance peak of the Ag@SiO_(2)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@SiO_(2)nanoparticle film surpassing that of uncoated pure silver nanoparticles.The Ag@SiO_(2)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.