Samarasekera Champika, Tan Bo, Venkatakrishnan Krishnan
Department of Aerospace Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, M5B 2K3, Canada.
Nanoscale Res Lett. 2012 Jul 18;7(1):404. doi: 10.1186/1556-276X-7-404.
The current state-of-the-art in nanotip synthesis relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. To realize their ultimate potential, synthesized nanotips require simpler fabrication techniques that allow for control over their final nano-morphology. We present a unique, dry, catalyst-free, and ambient condition method for creating densely clustered, flower-like, sodium oxide (Na2O) nanotips with controllable tip widths. Femtosecond laser ablation of a soda-lime glass substrate at a megahertz repetition rate, with nitrogen flow, was employed to generate nanotips with base and head widths as small as 100 and 20 nm respectively, and lengths as long as 10 μm. Control of the nanotip widths was demonstrated via laser dwell time with longer dwell times producing denser clusters of thinner nanotips. Energy dispersive X-ray analysis reveals that nanotip composition is Na2O. A new formation mechanism is proposed, involving an electrostatic effect between ionized nitrogen and polar Na2O. The synthesized nanotips may potentially be used in antibacterial and hydrogen storage applications.
当前纳米尖端合成的先进技术依赖于使用复杂的前驱体化学物质、催化剂或真空条件，以及它们的任何组合的技术。为了实现其最终潜力，合成的纳米尖端需要更简单的制造技术，以便能够控制其最终的纳米形态。我们提出了一种独特的、干式的、无催化剂的、在环境条件下的方法，用于制造具有可控尖端宽度的密集簇状、花状氧化钠（Na₂O）纳米尖端。采用兆赫兹重复频率的飞秒激光在氮气气流下对钠钙玻璃基板进行烧蚀，以产生基部和头部宽度分别小至100纳米和20纳米、长度长达10微米的纳米尖端。通过激光停留时间证明了对纳米尖端宽度的控制，停留时间越长，产生的更细纳米尖端的簇就越密集。能量色散X射线分析表明纳米尖端的成分是Na₂O。提出了一种新的形成机制，涉及电离氮和极性Na₂O之间的静电效应。合成的纳米尖端可能潜在地用于抗菌和储氢应用。
