Substrate Effect on the Refractive Index Sensitivity of Silver Nanoparticles

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• 作者：Erik Martinsson ; Marinus A. Otte ; Mohammad Mehdi Shahjamali ; Borja Sepulveda ; Daniel Aili
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：October 23, 2014
• 年：2014
• 卷：118
• 期：42
• 页码：24680-24687
• 全文大小：402K
• ISSN：1932-7455

文摘

The bulk refractive index (RI) sensitivity of dispersed and immobilized silver nanoparticles of three different shapes (spheres, cubes, and plates) is investigated. We demonstrate, both experimentally and theoretically, that the influence of immobilization on the RI sensitivity is highly dependent on the shape of the nanoparticles. A strong correlation is seen between the fraction of the particle surface area in direct contact with the substrate and the decrease in RI sensitivity when the particles are immobilized on a glass substrate. The largest decrease (鈭?6%) is seen for the most sensitive nanoparticles (plates), drastically reducing their advantage over other nanoparticle shapes. The shape-dependent substrate effect is thus an important factor to consider when designing nanoplasmonic sensors based on colloidal noble-metal nanoparticles.