Departamento de Química Física I, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain.
Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain.
Science. 2017 Nov 3;358(6363):640-644. doi: 10.1126/science.aan8478.
The irradiation of gold nanorod colloids with a femtosecond laser can be tuned to induce controlled nanorod reshaping, yielding colloids with exceptionally narrow localized surface plasmon resonance bands. The process relies on a regime characterized by a gentle multishot reduction of the aspect ratio, whereas the rod shape and volume are barely affected. Successful reshaping can only occur within a narrow window of the heat dissipation rate: Low cooling rates lead to drastic morphological changes, and fast cooling has nearly no effect. Hence, a delicate balance must be achieved between irradiation fluence and surface density of the surfactant on the nanorods. This perfection process is appealing because it provides a simple, fast, reproducible, and scalable route toward gold nanorods with an optical response of exceptional quality, near the theoretical limit.
用飞秒激光辐照金纳米棒胶体，可以调节来诱导可控的纳米棒整形，得到具有特别窄的局域表面等离子体共振带的胶体。该过程依赖于一个特征为温和的多次纵横比减小的模式，而棒的形状和体积几乎不受影响。成功的整形只能在散热率的一个狭窄窗口内发生：低冷却速率导致剧烈的形态变化，而快速冷却几乎没有效果。因此，必须在辐照强度和纳米棒上表面活性剂的表面密度之间达到微妙的平衡。这个完美的过程很有吸引力，因为它提供了一种简单、快速、可重复且可扩展的方法，使金纳米棒具有接近理论极限的卓越质量的光学响应。
