Name: Synthesizing Metal Nanoparticles and Nanostructures Using Ultrafast Laser Ablation
Uploaded: 2023-06-16T14:20:00
Description: Watch this Scientific Journal Video about Synthesizing Metal Nanoparticles and Nanostructures Using Ultrafast Laser Ablation at JoVE.com

synthesizing metal nanoparticles and nanostructures using ultrafast laser ablation

通过激光烧蚀合成纳米颗粒和纳米结构

Ultrafast laser ablation is a rapidly evolving field of laser-material interactions. High-intensity laser pulses with pulse durations in the femtosecond (fs) to picosecond (ps) range are used to generate precise material ablation. Compared to nanosecond (ns) laser pulses, ps laser pulses can ablate materials with higher precision and accuracy due to their shorter pulse duration. They can generate less collateral damage, debris, and contamination of the ablated material due to fewer thermal effects. However, ps lasers are typically more expensive than ns lasers and need specialized expertise for operation and maintenance. The ultrafast laser pulses enable precise control over the energy deposition, which leads to highly localized and minimized thermal damage to the surrounding material. Additionally, ultrafast laser ablation can lead to the generation of unique nanomaterials (i.e., surfactants/capping agents are not obligatory during the production of nanomaterials). Therefore, we can term this a green synthesis/fabrication method1,2,3. The mechanisms of ultrafast laser ablation are intricate. The technique involves different physical processes, such as (a) electronic excitation, (b) ionization, and (c) the generation of a dense plasma, which results in the ejection of material from the surface4. Laser ablation is a simple single-step process to produce nanoparticles (NPs) with high yield, narrow size distribution, and nanostructures (NSs). Naser et al.5 conducted a detailed review of the factors influencing the synthesis and production of NPs through the laser ablation method. The review covered various aspects, such as the parameters of a laser pulse, focusing conditions, and the ablation medium. The review also discussed their impact on producing a wide range of NPs using the laser ablation in liquid (LAL) method. The laser-ablated nanomaterials are promising materials, with applications in various fields such as catalysis, electronics, sensing, and biomedical, water splitting applications6,7,8,9,10,11,12,13,14.
Surface-enhanced Raman scattering (SERS) is a powerful analytical sensing technique that significantly enhances the Raman signal from probe/analyte molecules adsorbed onto metallic NSs/NPs. SERS is based on the excitation of surface plasmon resonances in metallic NPs/NSs, which results in a significant rise in the local electromagnetic field near the metallic nano-features. This enhanced field interacts with the molecules adsorbed on the surface, significantly enhancing the Raman signal. This technique has been used to detect various analytes, including dyes, explosives, pesticides, proteins, DNA, and drugs15,16,17. In recent years, significant progress has been made in the development of SERS substrates, including the use of differently shaped metallic NPs18,19 (nanorods, nanostars, and nanowires), hybrid NSs20,21 (a combination of the metal with other materials&#160;such as Si22,23, GaAs24, Ti25, graphene26, MOS227, Fe28, etc.), as well as flexible substrates29,30 (paper, cloth, nanofiber, etc.). Developing these new strategies in the substrates has opened up new possibilities for using SERS in various real-time applications.
This protocol discusses the fabrication of Ag NPs using a ps laser at different wavelengths and Ag-Au alloy NPs (with different ratios of Ag and Au targets) fabricated using laser ablation technique&#160;in distilled water. Additionally, silicon micro/nanostructures are created using an fs laser on silicon in the air. These NPs and NSs are characterized using ultraviolet (UV)-visible absorption, transmission electron microscopy (TEM), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM). Furthermore, the preparation of SERS substrates and analyte molecules are discussed, followed by the collection of Raman and SERS spectra of the analyte molecules. Data analysis is performed to determine the enhancement factor, sensitivity, and reproducibility of the laser-ablated NPs/NSs as potential sensors. Additionally, typical SERS studies are discussed, and the SERS performance of hybrid substrates is evaluated. Specifically, it has been found that the promising gold nanostars&#39; SERS sensitivity can be enhanced approximately 21 times by using laser-structured silicon instead of plain surfaces (such as Si/glass) as a base.

作者聚焦：通过液体中的激光烧蚀进行纳米颗粒合成的进展和应用 

超快激光烧蚀纳米颗粒和纳米结构在基于表面增强拉曼散射的传感应用中的应用

Laser ablation and liquids technique focuses on synthesizing nanoparticles and nanostructures by ablating a target material in liquid or gas environment, forming ecofriendly nanoparticles without any surfactants. This research scope involves refining the laser parameters, analyzing nanoparticle properties, exploring synthesis mechanisms, and discovering applications in various fields such as catalysis, sensing, electronics, energy storage, and biomedical imaging. Recent developments in laser ablation for nanomaterial fabrication involve tailoring the nanoparticle sizes, shapes, and composition, scalable production methods, hybrid nanomaterial synthesis, and surface functionalization.These advances offer improved stability, extended shelf life, high scalability that is up to few grams per hour, and commercially viable colloidal nanoparticles and surface nanostructures production for diverse applications. In recent times, various other improvisations such as ultrafast vessel beam and vortex beam ablation processes have been implemented to generate exotic nanostructures, as well as nanoparticles, with tuneable shapes, sizes, and topographies. Technologies advancing nanoparticle synthesis via ultrafast laser ablation include molecular dynamic simulations for understanding the formation of these nanoparticles.Precise control for tailoring nanoparticle size, shape, and composition in C.2 TEM characterization and real time monitoring techniques. The experimental challenges involved are automation techniques through improved instrumentation and technology, addressing the initial establishment cost of the laser ablation technique itself, ensuring proper sample preparation, controlling the contamination, and announcing data analysis and interpretation for increased accuracy and reliability of the results. In our laboratory, we have investigated diverse materials such as gold, silver, zinc, titanium, copper, silicone, gallium arsenide, germanium, graphene oxide, Hafnium, and various biome metallic, trimetallic, and plus monoxides.Laser ablation experiments were conducted in different environments using various focusing conditions for precise material processing and nanoparticle synthesis.

Watch this Scientific Journal Video about Synthesizing Metal Nanoparticles and Nanostructures Using Ultrafast Laser Ablation at JoVE.com

Synthesizing Metal Nanoparticles and Nanostructures Using Ultrafast Laser Ablation  

利用超快激光烧蚀合成金属纳米颗粒和纳米结构

首先，选择目标材料和周围的液体。使用丙酮对目标表面进行超声波清洁 15 分钟，以去除有机材料，例如油、油脂和蜡。再用乙醇对表面进行超声波清洗 15 分钟，以去除盐和糖等极性污染物。然后用去离子水使用超声波清洗 15 分钟清洁表面，以去除样品表面的任何残留溶剂或污染物。消融前测量样品的重量，然后对样品进行激光烧蚀实验。烧蚀实验后再次测量样品的重量。通过比较烧蚀前后样品的重量来估计实验过程中去除的材料量。接下来，将输入激光功率调整到大约 150 毫瓦，用于银靶的皮秒激光烧蚀。结合偏振片和半波片来调节激光脉冲能量。使用聚焦透镜将激光束聚焦到样品上，以烧蚀材料表面。使用Z方向的平移台手动调整激光在样品上的焦点，同时观察产生的明亮等离子体和发出的裂纹声。接下来，使用聚焦光学器件将激光束聚焦到样品上，具体取决于实现不同的烧蚀深度并改善对纳米颗粒和纳米结构合成的控制。将样品放置在连接到 ESP 控制器的 XY 载物台上，确保其垂直于激光传播方向移动。调整扫描速度和激光加工区域，以优化与样品相互作用的激光脉冲数量。在激光烧蚀过程中，在扫描样品的同时进行激光图案化，以达到所需的尺寸并防止单点烧蚀。接下来，对于液体中的激光烧蚀，进行激光烧蚀实验。监控激光功率和其他设置以保持一致性。在实验过程中持续观察目标材料，确保激光束聚焦在所需区域。银胶体纳米颗粒的吸收光谱显示，在420、394和403纳米处，不同激光波长的表面纤溶酶共振峰均存在。不同成分的银金合金纳米颗粒的归一化吸光度光谱显示，随着金百分比从0增加到100，表面纤溶酶共振峰从410纳米偏移到519纳米。

Research

JoVE Journal

Engineering

Synthesizing Metal Nanoparticles and Nanostructures Using Ultrafast Laser Ablation

Ultrafast Laser-Ablated Nanoparticles and Nanostructures for Surface-Enhanced Raman Scattering-Based Sensing Applications

The technique of ultrafast laser ablation in liquids has evolved and matured over the past decade, with several impending applications in various fields ...