Cluster formation of nanoparticles in an optical trap studied by fluorescence correlation spectroscopy
Cluster formation of nanoparticles in an optical trap studied by fluorescence correlation spectroscopy
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DOI：
10.1103/physreve.72.021408
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发表时间：
2005-08-01
影响因子：
2.4
通讯作者：
Masuhara, H
中科院分区：
文献类型：
--
作者：
Hosokawa, C;Yoshikawa, H;Masuhara, H
我们报告在现场观察团簇生长的纳米粒子被限制在一个光阱势通过荧光相关光谱。当由高度聚焦的激光束引起的光学捕获力作用于纳米颗粒悬浮液时，纳米颗粒的数量增加，并且可以在焦点处形成组装体。研究了荧光自相关曲线的衰减时间随激光照射时间和激光功率的变化关系。在光学组装的初始阶段，衰减时间随激光束的照射时间而增加。另一方面，在后期，观察到衰减时间的减少。用弱光阱和强光阱下的布朗运动模型成功地解释了这一现象。结果表明，纳米粒子的捕获和聚集是同时进行的，聚集体被限制在焦斑中自发地形成更大的聚集体。
We report in situ observation of cluster growth of nanoparticles confined in an optical trapping potential by means of fluorescence correlation spectroscopy. When an optical trapping force caused by a highly focused laser beam acts on nanoparticle suspensions, the number of nanoparticles increases and an assembly can be formed at the focal spot. The decay times of fluorescence autocorrelation curves were investigated as a function of the irradiation time of the laser beam and the laser power. In the initial stage of the optical assembling, the decay time increases with the irradiation time of the laser beam. On the other hand, in the later stage, a decrease of the decay time was observed. This behavior is explained successfully by using two models of Brownian motion under weak and strong optical trapping. It was revealed that trapping and clustering of nanoparticles proceed simultaneously and clusters confined in the focal spot make larger aggregates spontaneously.