Electrically Modulated Localized Surface Plasmon around Self-Assembled-Monolayer-Covered Nanoparticles

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• 作者：Liyuan Ma ; Shandong Xu ; Chaoming Wang ; Haining Wang ; Shengli Zou ; Ming Su
• 刊名：Langmuir
• 出版年：2017
• 出版时间：February 14, 2017
• 年：2017
• 卷：33
• 期：6
• 页码：1437-1441
• 全文大小：359K
• ISSN：1520-5827

文摘

This article reports the observation of electrical modulation of localized surface plasmon around self-assembled monolayer (SAM)-modified gold nanoparticles and the establishment of a new spectroscopy technique, that is, dynamic electro-optical spectroscopy (DEOS). The gold nanoparticles are deposited onto a transparent conductive substrate, and an electrical bias applied on the conductive substrate can cause shift of resonance plasmon response, where the direction of peak shift is related to the polarity of applied bias. The peak shift observed at 2.4 V is approximately ten times larger than those reported in previous work. It is postulated that significant peak shift is the result of reorientation of adsorbed water on electrode, which can change local dielectric environment of nanoparticles. An energy barrier is identified when adsorbed water molecules are turned from oxygen-down to oxygen-up. Frequency-dependent peak shifts on surface-modified gold nanoparticles show that reorientation is a fast reversible process with rich dynamics.