Mechanistic Aspect of Surface Modification on Glass Substrates Assisted by Single Shot Pulsed Laser-Induced Fragmentation of Gold Nanoparticles
Mechanistic Aspect of Surface Modification on Glass Substrates Assisted by Single Shot Pulsed Laser-Induced Fragmentation of Gold Nanoparticles
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DOI：
10.1021/jp106830x
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发表时间：
2011-03-31
影响因子：
3.7
通讯作者：
Shiraishi, Ryowya
中科院分区：
文献类型：
--
作者：
Hashimoto, Shuichi;Uwada, Takayuki;Shiraishi, Ryowya
本文描述了对组装有 47 +/- 8 nm 金纳米粒子并暴露于单次 532 nm 纳秒脉冲激光的硼硅酸盐玻璃基板的光改性机理研究。采用180～430 mJ cm(-2)脉冲(-1)的激光注量，其值比15～20 J cm(-2)脉冲(-1)的石英击穿阈值低2个数量级。光改性后，玻璃表面形成直径约 20 nm、深度约 10 tun 的凹坑，同时激光诱导金纳米颗粒分裂，生成直径 15 nm 的更小的颗粒。凹坑的数密度随着激光注量的增加而急剧增加，其开始发生在类似于160-170 mJ cm(-2)脉冲(-1)时，并达到原始Au颗粒数密度的两倍(150+/-10颗粒μ m(-2))，并且在高注量下趋于平稳。弹坑形成的开始与金纳米颗粒的分裂同时发生，这是由于吸收激光能量导致温度升高到金的沸点以上。因此，金纳米颗粒的爆炸性蒸发被认为对于此处观察到的修饰起着至关重要的作用。由于金的突然蒸发而导致的与激光注量相关的热声压的估计为这一假设提供了坚实的支持。这一发现可能代表了纳米颗粒激光烧蚀/破碎在材料加工中的新应用。
This paper describes the mechanistic investigation on the photomodification of a borosilicate glass substrate assembled with 47 +/- 8 nm gold nanoparticles and exposed to a single shot of 532 nm nanosecond pulsed-laser light. The laser fluences ranging from 180 to 430 mJ cm(-2) pulse(-1), the values of which are 2 orders of magnitude lower than the breakdown threshold of quartz of 15-20 J cm(-2) pulse(-1) were used. Upon photomodification, the craters of similar to 20 nm diameter and similar to 10 tun depth were formed on the glass surface simultaneously with the laser-induced splitting of Au nanopartides to generate smaller particles of 15 nm diameter. The number density of the craters increased depending on the laser fluence with a sharp rise, the onset of which occurred at similar to 160-170 mJ cm(-2) pulse(-1), and reached a value of twice the number density of original Au particles (150 +/- 10 particles mu m(-2)) with a weak tendency to level off at high fluences. The onset of the crater formation coincides with splitting of gold nanopartides due to the temperature rise above the boiling point of gold resulting from the absorption of the laser energy. Thus, the explosive evaporation of gold nanoparticles is postulated to play a crucial role for the modification observed here. This assumption gained a solid support from the estimation of laser fluence-dependent thermoacoustic pressures due to the sudden evaporation of gold. This finding may represent a new application of the laser ablation/fragmentation of nanoparticles to material processing.