Sorbonne Paris Cité, Paris Diderot University, ITODYS, CNRS-UMR 7086, 15 rue Jean de Baif, F-75013 Paris, France.
Sorbonne Paris Cité, Université Paris Descartes, Neurophotonics Laboratory, CNRS-UMR 8250, 45 rue des Saints-Pères, F-75006 Paris, France.
Faraday Discuss. 2016 Dec 12;193:339-352. doi: 10.1039/c6fd00098c.
Although extremely sensitive, electrical measurements are essentially unable to discriminate complex chemical events involving individual nanoparticles. The coupling of electrochemistry to dark field imaging and spectroscopy allows the triggering of the electrodissolution of an ensemble of Ag nanoparticles (by electrochemistry) and the inference of both oxidation and dissolution processes (by spectroscopy) at the level of a single nanoparticle. Besides the inspection of the dissolution process from optical scattering intensity, adding optical spectroscopy reveals chemical changes through drastic spectral changes. The behaviours of single NPs and NP agglomerates are differentiated: in the presence of thiocyanate ions, the transformation of Ag single nanoparticles to AgSCN is investigated in the context of plasmonic coupling with the electrode; tentative interpretations for optically unresolved groups of nanoparticles are proposed.
尽管极其灵敏，电测量在本质上无法区分涉及单个纳米粒子的复杂化学事件。电化学与暗场成像和光谱学的结合允许在单个纳米粒子的水平上触发 Ag 纳米粒子（通过电化学）的共电溶解，并推断出氧化和溶解过程（通过光谱学）。除了通过光学散射强度检查溶解过程之外，添加光学光谱学通过剧烈的光谱变化揭示化学变化。可以区分单个 NPs 和 NP 聚集体的行为：在硫氰酸根离子存在的情况下，研究了在与电极的等离子体耦合的背景下，Ag 单纳米粒子向 AgSCN 的转化；对于在光学上无法分辨的纳米粒子群，提出了暂定的解释。
