Bongiovanni Gabriele, Olshin Pavel K, Yan Chengcheng, Voss Jonathan M, Drabbels Marcel, Lorenz Ulrich J
Laboratory of Molecular Nanodynamics, École Polytechnique Fédérale de Lausanne 1015 Lausanne Switzerland
Nanoscale Adv. 2021 Aug 2;3(18):5277-5283. doi: 10.1039/d1na00406a. eCollection 2021 Sep 14.
Plasmonic nanoparticles in aqueous solution have long been known to fragment under irradiation with intense ultrafast laser pulses, creating progeny particles with diameters of a few nanometers. However, the mechanism of this process is still intensely debated, despite numerous experimental and theoretical studies. Here, we use electron microscopy to directly observe the femtosecond laser-induced fragmentation of gold nanoparticles in water, revealing that the process occurs through ejection of individual progeny particles. Our observations suggest that the fragmentation mechanism involves Coulomb fission, which occurs as the femtosecond laser pulses ionize and melt the gold nanoparticle, causing it to eject a highly charged progeny droplet. Subsequent Coulomb fission events, accompanied by solution-mediated etching and growth processes, create complex fragmentation patterns that rapidly fluctuate under prolonged irradiation. Our study highlights the complexity of the interaction of plasmonic nanoparticles with ultrafast laser pulses and underlines the need for observations to unravel the mechanisms of related phenomena.
长期以来，人们一直知道水溶液中的等离子体纳米颗粒在强超快激光脉冲照射下会发生碎片化，产生直径为几纳米的子代颗粒。然而，尽管进行了大量的实验和理论研究，这一过程的机制仍存在激烈争论。在这里，我们使用电子显微镜直接观察飞秒激光诱导的水中金纳米颗粒的碎片化，发现该过程是通过单个子代颗粒的喷射发生的。我们的观察结果表明，碎片化机制涉及库仑裂变，这是在飞秒激光脉冲使金纳米颗粒电离并熔化时发生的，导致其喷射出一个高电荷的子代液滴。随后的库仑裂变事件，伴随着溶液介导的蚀刻和生长过程，产生了复杂的碎片化模式，在长时间照射下会迅速波动。我们的研究突出了等离子体纳米颗粒与超快激光脉冲相互作用的复杂性，并强调了通过观察来揭示相关现象机制的必要性。
