Study of Heat Transfer Dynamics from Gold Nanorods to the Environment via Time-Resolved Infrared Spectroscopy
Study of Heat Transfer Dynamics from Gold Nanorods to the Environment via Time-Resolved Infrared Spectroscopy
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DOI：
10.1021/acsnano.5b06623
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发表时间：
2016-02-01
期刊：
影响因子：
17.1
通讯作者：
Alivisatos, A. Paul
中科院分区：
文献类型：
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作者：
Nguyen, Son C.;Zhang, Qiao;Alivisatos, A. Paul
研究纳米粒子周围的局部溶剂对于理解粒子与其环境之间的能量交换动力学非常重要，并且需要能够动态探测与纳米粒子附近接触的溶剂区域的光谱方法。在这项工作中，我们演示了使用时间分辨红外光谱在数百皮秒的时间尺度上跟踪当地水的振动模式的变化，揭示了从金纳米棒到当地水环境的传热动力学。我们将该探针应用于由有机 CTAB 双层封端的金纳米棒以及涂有不同厚度的无机介孔二氧化硅的金纳米棒组成的原型等离子体光热系统。 CTAB 封端的金纳米棒的传热时间常数约为 350 ps，并且随着激光激发功率的增加而变得更快，最终由于局部溶剂过热而产生气泡。纳米棒的二氧化硅涂层减缓了传热并抑制过热气泡的形成。
Studying the local solvent surrounding nanoparticles is important to understanding the energy exchange dynamics between the particles and their environment, and there is a need for spectroscopic methods that can dynamically probe the solvent region that is in nearby contact with the nanoparticles. In this work, we demonstrate the use of time resolved infrared spectroscopy to track changes in a vibrational mode of local water on the time scale of hundreds of picoseconds, revealing the dynamics of heat transfer from gold nanorods to the local water environment. We applied this probe to a prototypical plasmonic photothermal system consisting of organic CTAB bilayer capped gold nanorods, as well as gold nanorods coated with varying thicknesses of inorganic mesoporous-silica. The heat transfer time constant of CTAB capped gold nanorods is about 350 ps and becomes faster with higher laser excitation power, eventually generating bubbles due to superheating in the local solvent. Silica coating of the nanorods slows down the heat transfer and suppresses the formation of superheated bubbles.