Methodological Improvement in Pulsed Laser-Induced Size Reduction of Aqueous Colloidal Gold Nanoparticles by Applying High Pressure
Methodological Improvement in Pulsed Laser-Induced Size Reduction of Aqueous Colloidal Gold Nanoparticles by Applying High Pressure
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DOI：
10.1021/jp300690z
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发表时间：
2012-02
影响因子：
3.7
通讯作者：
D. Werner;Tomoyuki Ueki;S. Hashimoto
中科院分区：
文献类型：
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作者：
D. Werner;Tomoyuki Ueki;S. Hashimoto
通过施加远高于水的临界压力（22.1 MPa）的高压，我们使用纳秒脉冲激光诱导尺寸减小技术制备了金纳米颗粒（Au NPs）。由此获得的Au NPs表现出依赖于所施加的激光能量密度（注量）的窄尺寸分布和尺寸选择性。这一点很重要，因为之前在环境压力下的尝试未能实现这种尺寸选择性生成。以牺牲原始刻面的58 nm Au NP为代价，获得了直径为46和33 nm的球形Au NP，标准偏差仅为2-3 nm。我们归因于我们的结果形成的超临界水层周围的液滴NP通过激光加热转化。超临界层源于颗粒的热传递，导致水温高于647 K的临界点。超临界水层作为光热逐层减小尺寸的有效散热器，以释放小碎片，留下...
By applying high pressures well above the critical pressure of water (22.1 MPa), we prepared gold nanoparticles (Au NPs) using a nanosecond pulsed laser-induced size-reduction technique. The Au NPs thus obtained exhibited a narrow size distribution and size-selectivity dependent on the applied laser energy density (fluence). This is significant because previous attempts under ambient pressure failed to achieve such size-selective generation. Spherical Au NPs of diameters 46 and 33 nm, with a standard deviation of only 2–3 nm, were obtained at the expense of original faceted 58 nm Au NPs. We ascribed our results to the formation of a supercritical water layer surrounding the liquid droplet NP transformed by laser heating. The supercritical layer originates from heat transfer from the particle, leading to water temperatures above the critical point of 647 K. The supercritical water layer acts as an effective heat sink for photothermal layer-by-layer size reduction to release small fragments, leaving behind ...