Frequency dependence of gold nanoparticle superassembly by dielectrophoresis
Frequency dependence of gold nanoparticle superassembly by dielectrophoresis
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DOI：
10.1021/la701472y
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发表时间：
2007-11-20
期刊：
影响因子：
3.9
通讯作者：
Collins, Scott D.
中科院分区：
文献类型：
--
作者：
Gierhart, Brian C.;Howitt, David G.;Collins, Scott D.
介电泳法是一种捕获纳米颗粒并将其组装成纳米结构的有效方法。介电交流电场的频率极大地影响了所得到的纳米颗粒组装物的形貌。在这项研究中，识别了与特定的金纳米颗粒组装形态相关的频率区域。用不同电场频率的微电极将悬浮在水中的金纳米颗粒捕获到氮化硅薄膜上。用透射电子显微镜观察了所得到的组装体。对于该体系，对形态的主要频率依赖影响似乎不是来自介电泳力本身的Clausius-Mossotti因子，而是来自交流电渗透流体流动和电极-溶液界面的双电层的影响。技术上感兴趣的频率范围包括形成一维纳米粒子链、微线、适合于纳米间隙电极形成的微线和纳米粒子链的组合，以及具有非常高表面积的致密三维组件。
Dielectrophoresis is an effective method for capturing nanoparticles and assembling them into nanostructures. The frequency of the dielectrophoretic alternating current (ac) electric field greatly influences the morphology of resultant nanoparticle assemblies. In this study, frequency regimes associated with specific gold nanoparticle assembly morphologies were identified. Gold nanoparticles suspended in water were captured by microelectrodes at different electric field frequencies onto thin silicon nitride membranes. The resultant assemblies were examined by transmission electron microscopy. For this system, the major frequency-dependent influence on morphology appears to arise not from the Clausius-Mossotti factor of the dielectrophoretic force itself, but instead from ac electroosmotic fluid flow and the influence of the electrical double layer at the electrode- solution interface. Frequency regimes of technological interest include those forming one-dimensional nanoparticle chains, microwires, combinations of microwires and nanoparticle chains suitable for nanogap electrode formation, and dense three-dimensional assemblies with very high surface area.