基于Au纳米颗粒的稳定性、无毒性、生物相容性和Ag纳米颗粒优异的消光特性,Au-Ag合金纳米颗粒在生物传感中存在着潜在的应用价值。为了能找到传感性能更好的合金纳米颗粒,本文利用双层球Mie散射理论和介电函数尺寸修正模型定量研究了Au-Ag合金纳米球壳的尺寸参数对折射率灵敏度、半峰宽和品质因子的影响,获得了最佳品质因子和对应的优化尺寸。同时,本文研究了Au摩尔分数对最佳品质因子和优化尺寸的影响。结果发现,当Au摩尔分数x为0.5时,Au-Ag@SiO2(Au-Ag@Vacuum)合金纳米球壳的最大品质因子为2.09(2.20),对应的内核半径和外壳厚度分别为22.3 nm(23.6 nm)和8.7 nm(6.9 nm)。当Au摩尔分数小于0.25时,Au-Ag合金纳米球壳的品质因子优于Au纳米球壳。随着Au摩尔分数的减小,品质因子增大,甚至是Au纳米球壳的2~3倍。此研究为Au-Ag合金纳米球壳在生物传感领域中的有效应用提供了理论指导。
Abstract
Based on the stability, nontoxicity, and biocompatibility of Au nanoparticles and excellent extinction properties of Ag nanoparticles, bimetallic alloy nanoparticles have potential value for applications in biosensors. In order to find alloy nanoparticles with better sensing properties, the effects of the size of Au-Ag nanoshell on Refractive Index Sensitivity, Full Width at Half Maximum, and Figure of Merit were quantitatively studied, by adopting Mie scattering theory of sphere with a concentric spherical shell and the size correction model of the dielectric function. Thus the optimal Figure of Merit and the corresponding size were obtained.Meanwhile, this article studied the effect of Au molar fraction on the optimum Figure of Merit and size was studied. The results show that when Au molar fraction x is fixed at 0.5, the Figure of Merit of Au-Ag@SiO2 nanoshell reaches its maximum value (2.09) and the corresponding core radius and shell thickness are 22.3 nm and 8.7 nm, respectively. The Figure of Merit of Au-Ag@Vacuum nanoshell reaches its maximum value (2.20) and the corresponding core radius and shell thickness are 23.6 nm and 6.9 nm, respectively. When the Au molar fraction is less than 0.25, the Figure of Merit of Au-Ag nanoshell is better than that of Au nanoshell. With the decrease of the Au molar fraction, the Figure of Merit increases to at most 2-3 times of the Au nanoshell. This study provides theoretical guidance for the effective application of Au-Ag nanoshell in the field of biosensors.
关键词
Au-Ag合金纳米球壳 /
Mie理论 /
传感 /
品质因子 /
局域表面等离激元共振
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Key words
Au-Ag nanoshell /
Mie theory /
Sensing /
Figure of Merit /
Localized Surface Plasmon Resonance
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参考文献
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脚注
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基金
国家自然科学基金项目(11764042),新疆维吾尔自治区“百名青年博士引进计划”项目
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