Mansour Yehia, Battie Yann, En Naciri Aotmane, Chaoui Nouari
LCP-A2MC, Institut Jean Barriol, Université de Lorraine, 1 Boulevard Arago, 57070 Metz, France.
Nanoscale. 2019 Jun 20;11(24):11679-11686. doi: 10.1039/c9nr01206k.
We propose an advanced photothermal model based on a modified Takami model (MTM) to explain the mechanisms of shape changes of colloidal gold nanorods (NRs) induced by nanosecond laser pulses. This model takes into account the orientation of NRs, the radiative and convective losses, and the phase transitions of NRs. It was applied to the determination of the evolution of temperature and the shape and size transformations of NRs during the laser exposure. A series of measurements arising from the interaction between Au NRs and nanosecond laser pulses were analyzed by TEM measurements and the MTM model. We have demonstrated that the fragmentation and reshaping processes govern the nanoparticle (NP) shape. At high laser fluence, the complete fragmentation leads to a population of nearly spherical NPs, while at a moderate laser fluence, the partial fragmentation and reshaping processes generate a bimodal distribution. At low laser fluence, uncommon φ-shape NPs were produced as a result of the competition of cooling and reshaping processes. We also demonstrated that it is possible by the MTM model to determine the laser fluence required to suppress some specific NR shapes and to predict the NP size and shape distributions obtained after the laser exposure.
我们提出了一种基于改进的高见模型（MTM）的先进光热模型，以解释纳秒激光脉冲诱导的胶体金纳米棒（NRs）形状变化的机制。该模型考虑了NRs的取向、辐射和对流损失以及NRs的相变。它被应用于确定激光照射期间NRs的温度演变以及形状和尺寸变化。通过透射电子显微镜（TEM）测量和MTM模型分析了一系列由金纳米棒与纳秒激光脉冲相互作用产生的测量结果。我们已经证明，破碎和重塑过程决定了纳米颗粒（NP）的形状。在高激光通量下，完全破碎导致形成大量近乎球形的NP，而在中等激光通量下，部分破碎和重塑过程产生双峰分布。在低激光通量下，由于冷却和重塑过程的竞争，产生了不常见的φ形NP。我们还证明，通过MTM模型可以确定抑制某些特定NR形状所需的激光通量，并预测激光照射后获得的NP尺寸和形状分布。
