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

レーザーアブレーションによるナノ粒子とナノ構造の合成

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.

著者スポットライト:液体中のレーザーアブレーションによるナノ粒子合成の進歩と応用 

表面増強ラマン散乱ベースのセンシングアプリケーションのための超高速レーザーアブレーションナノ粒子およびナノ構造

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  

超高速レーザーアブレーションによる金属ナノ粒子・ナノ構造の合成

まず、ターゲット材料と周囲の液体を選択します。アセトンを使用して対象表面を15分間超音波洗浄し、油、グリース、ワックスなどの有機物を取り除きます。表面をさらに15分間エタノールで超音波洗浄し、塩や糖などの極性汚染物質を取り除きます。次に、超音波洗浄を使用して15分間の脱イオン水で表面を洗浄し、サンプルの表面から残留溶媒や汚染物質を取り除きます。アブレーション前にサンプルの重量を測定し、サンプルに対してレーザーアブレーション実験を行います。アブレーション実験後、サンプルの重量を再度測定します。アブレーション前後のサンプルの重量を比較することにより、実験中に除去された材料の量を推定します。次に、入力レーザー出力を約150ミリワットに調整して、銀ターゲットのピコ秒レーザーアブレーションを行います。偏光子と半波長板を組み合わせて、レーザーパルスエネルギーを調整します。集光レンズを使用してレーザービームをサンプルに集束させ、材料表面をアブレーションします。Z方向の並進ステージを使用して、レーザーのサンプルへの焦点を手動で調整し、生成された明るいプラズマと発せられる割れる音を観察します。次に、集光光学系を使用して、さまざまなアブレーション深度を達成し、ナノ粒子とナノ構造の合成の制御を改善することに応じて、レーザービームをサンプルに集束させます。ESPコントローラーに接続されたXYステージにサンプルを配置し、レーザーの伝搬方向に対して垂直に移動するようにします。スキャン速度とレーザー加工領域を調整して、サンプルと相互作用するレーザーパルスの数を最適化します。レーザーアブレーションプロセスでは、サンプルをスキャンしながらレーザーパターニングを行い、目的の寸法を達成し、シングルポイントアブレーションを防ぎます。次に、液体中でのレーザーアブレーションについて、レーザーアブレーション実験を行います。レーザー出力やその他の設定を監視して、一貫性を維持します。実験中もターゲット材料を継続的に観察し、レーザービームが目的の領域に焦点を合わせていることを確認します。銀コロイドナノ粒子の吸収スペクトルから、レーザー波長の違いから、420、394、403ナノメートルで表面プラスミン共鳴ピークが観察されたことが明らかになりました。組成の異なる銀金合金ナノ粒子の正規化された吸光度スペクトルは、金の割合がゼロから100に増加するにつれて、表面プラスミン共鳴のピークが410ナノメートルから519ナノメートルにシフトすることを明らかにしました。

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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 ...