Pulsed Laser Ablation Research Articles

Femtosecond laser synthesis of YAG:Ce3+ nanoparticles in liquid

YAG:Ce3+ nanocrystals are promising bio-labeling materials due to their low toxicity and high photostability. It is in demand to efficiently synthesize YAG:Ce3+ nanocrystals of a small size. Pulse laser ablation is an approach to produce nanoparticles directly from bulk materials with the advantages of smaller particle sizes and lower production costs. Here, we present the synthesis of YAG:Ce3+ nanocrystals from bulk crystal using the femtosecond laser ablation method in liquid. Comparing the liquid environment, we demonstrated that the lauryl dimethylaminoacetic acid betain (LDA) aqueous solution is preferred for the formation of smaller-sized YAG:Ce3+ nanoparticles than deionized water due to the attractiveness between the LDA molecules and the YAG:Ce3+ nanoparticles. We also verified that the high laser repetition rate had no effect on the average size of YAG:Ce3+ nanocrystals, where the fragmentation process is saturated under a high laser repetition rate. This study provides a simple and effective method to synthesize small size YAG:Ce3+ nanoparticles by femtosecond laser ablation in liquid.

Characterization of hydrophobic metasurfaces fabricated on Ni-Mn-Ga-based alloys using femtosecond pulsed laser ablation

The generation of hydrophobic surfaces through laser ablation has garnered considerable attention, particularly for its prospective diverse applications across various industries. This study explores the possibility of generating controllable hydrophobic metasurfaces on Ni-Mn-Ga-based magnetic shape memory (MSM) alloys using femtosecond pulse width laser (FPWL). While hydrophobic surfaces have been achieved on different materials through a variety of different techniques, the research marks the first systematic attempt to tailor hydrophobicity on the surface of Ni-Mn-Ga-based alloys. By characterizing surfaces treated with different laser parameters, the distinct morphologies and hydrophobic properties corresponding to each surface were identified. This newfound control over surface properties with specific machining parameters opens possibilities for applications in microfluidic devices. Additionally, the potential of utilizing the magnetic-field-induced strain (MFIS) exhibited by Ni-Mn-Ga single crystals to alter surface hydrophobicity was explored. Metasurfaces mimicking the dimensional changes in elongation induced by MFIS demonstrated higher static contact angles (SCAs) for water droplets compared to the original surfaces. This approach presents a promising avenue for creating multifunctional microdevices with controllable hydrophobicity using Ni-Mn-Ga-based alloys. Our findings not only offer insights into tailoring of hydrophobic/hydrophilic properties on Ni-Mn-Ga-based MSM alloys but also provide a novel methodology for fabricating functional metasurfaces on other metals.

The influence of surfactant type on the formation of zinc oxide nanoparticles via liquid phase pulsed laser ablation technique

The influence of surfactant type on the formation of zinc oxide nanoparticles via liquid phase pulsed laser ablation technique

Dual‐Stoichiometry Copper Sulphide Nanoparticles by Laser Ablation in DMSO: Synthesis and Biomedical Applications for Enhanced Photothermal Therapy and Photoacoustic Imaging

AbstractCopper sulphide nanoparticles are synthesized by laser ablation of a copper target in DMSO by a 527 nm nanosecond pulsed laser. These nanoparticles have double stoichiometry (CuS and Cu1.8S) and crystalline structures, sizes under 30 nm, and they present substantial absorbance in the second near‐infrared window and photoluminescence in the visible region. The nanoparticles are used as photothermal and photoacoustic agents at 1080 nm and 1064 nm, respectively. Utilizing as a photothermal agent, these nanoparticles rapidly exhibit local heating, photothermal stability, and a temperature change of 52.2 °C within 300 s at 1 mg mL−1 concentration and 3.23 W cm−2 laser intensity. On the other hand, while employed as a photoacoustic agent, they enhanced the contrast significantly and increased the brightness proportional to their concentrations when compared to ultrasound imaging. Additionally, the biocompatibility properties of these nanoparticles were tested with cancer cells, and they were subjected to laser ablation to assess their photothermal effects. In this article, we demonstrate that copper sulphide nanoparticles synthesized by pulsed laser ablation hold great promise for photothermal and photoacoustic applications, especially in biomedical applications.

Ultra-sensitive axial strain and magnetic field sensor based on three reflection surface interference and harmonic vernier effect

A high-sensitivity fiber optic strain and magnetic field (MF) sensor is designed by two Fabry-Perot interferometers (FPI) cascading and harmonic Vernier effect. Two cascaded FPIs consist of an intrinsic FPI1 and an extrinsic FPI2. FPI1 is fabricated by femtosecond laser pulse ablation on the single-mode fiber core. Then, FPI1 and another single-mode fiber are inserted into a quartz capillary from both sides to form FPI2. By adjusting the cavity length of FPI2, the cascaded FPI1 and FPI2 can form a harmonic Vernier effect sensor. Due to FPI1 being a cantilever beam, it is not subjected to axial strain. The strain of the sensor acts on a longer capillary, resulting in an extension of the effective length of the strain and a many fold increase in the strain sensitivity of the sensor. Due to the compact cascading of FPI1 and FPI2, this strain sensor has a very small structural size. The sensor average strain sensitivity obtained from the experiment reached 260.05 pm/με. Due to the extremely high axial strain sensitivity of this strain sensor, adhering it to the magnetostrictive material results in the average MF sensitivity of 6.82 nm/mT, and the minimum MF intensity detected by the MF sensor is 0.1 mT. The temperature crosstalk of the MF sensor is 0.3 mT/°C.

Characterization and comparison of titanium dioxide nanoparticles prepared by microwave and pulse laser ablation liquid methods

This study synthesized titanium dioxide (TiO2) quickly and cheaply using microwaves and pulsed laser ablation. Titanium isopropoxide (Ti[OCH(CH3)2]4) was the precursor and deionized water (DIW) was the solvent and reducer for sub-micrometer particle production in microwave technique. TiO2 nanoparticles were synthesized in pulsed laser ablation liquid medium after a 5-minute preparation period in a 1200 W commercial microwave and a 1-hour annealing at 400°C. A Q-switched Nd:YAG laser with 480 mJ energy per pulse was used for 100, 200, and 300 pulses. Multiple methods, including XRD, BET, and EDX. XRD showed anatase TiO2 in microwave-synthesised nanoparticles. Pulsed laser ablation produced pure TiO2 nanoparticles with a brookite crystalline structure. In microwave BET analysis, TiO2 has a large surface area of 72.727 to 108.28 m2/g. BET analysis indicated 82.44 to 98.67 m2/g of TiO2 surface area by pulsed laser ablation. Strong titanium (Ti) and oxygen (O) peaks in microwave and pulsed laser ablation EDX tests showed nanoparticle purity.

High Energy Pulsed Laser Beam to Produce a Thin Layer of Crystalline Silver without Heating the Deposition Substrate and Its Catalytic Effects

Crystalline silver thin layers were obtained using high-energy pulsed laser ablation without the heating of the deposition substrate. The fluid Plateau–Rayleigh (PRI), Rayleigh–Taylor (RTI), and Richtmyer–Meshkov (RMI) instabilities, as well as the crown splash induced during the pulsed laser deposition (PLD) in the high energy regime, resulting in ring and pearl-shaped structures, offer the benefit of an increased sorption surface. These morphological structures obtained for the silver thin layers make them of interest for catalytic applications. This study addresses both fundamental and applied issues on the morphological structures obtained for the silver thin layers and their catalytic function in organic processes. In this sense, the catalytic action of the thin silver layer was highlighted by modifications of the Reactive Blue 21 dye (C.I.) in an aqueous solution with sodium bicarbonate. Specific investigations and analyses were carried out using electron microscopy and elemental analysis (SEM-EDX), atomic force microscopy (AFM) and profilometry, mass spectrometry, ablation plasma diagnosis, diffractograms (XRD), as well as IR spectroscopy (FTIR). In addition to the experimental investigation and analyses, the simulation of the ionization energy threshold was conducted in COMSOL for complementary evaluation on the involved processes and phenomena.

Laser-Induced Breakdown Spectroscopy Analysis of Sheet Molding Compound Materials

Sheet Molding Compound (SMC) materials are extensively utilized as high-voltage insulation materials in electrical equipment. SMC materials are prone to aging after long-term operation. Conducting non-destructive testing to assess their electrical and physicochemical properties is crucial for the safe operation of electrical equipment. This study identifies the optimal equipment parameters for testing SMC materials using Laser-Induced Breakdown Spectroscopy (LIBS) technology through experimental investigation and also explores the ablation characteristics of SMC under various laser parameters. The results indicate a significant positive correlation between the ablation depth and laser pulse number, while there is no correlation with single laser pulse energy. However, the ablation area demonstrates a strong positive correlation with both single laser pulse energy and laser pulse number. Additionally, LIBS spectral analysis provides elemental results comparable to Energy Dispersive Spectroscopy (EDS), facilitating the examination of variations in Na, Ti, Fe, Mg, Ca, and C elemental contents with depth. Moreover, an enhanced iterative Boltzmann plot method is suggested for calculating the plasma temperature using 21 Fe I spectral lines and the electron density using the Fe II 422.608 nm line. The variations of these plasma parameters with laser pulse number are documented, and the results show consistent trends, confirming that the laser-induced SMC plasma adheres to local thermodynamic equilibrium.

Engineering luminescent quantum dots through laser ablation of samarium oxide (Sm2O3): A novel approach for enhanced fiber optic gas sensing

Underexplored Sm2O3, with tunable redox and high-surface nanostructures, emerges as a promising volatile organic compounds (VOCs) sensor material for next-gen applications. This study presents the successful synthesis of novel Sm2O3 luminescent quantum dots using a unique pulsed laser ablation technique. Material characterization by FESEM, XRD, EDAX, and HRTEM confirmed the formation of cubic polycrystalline quantum dots. The optical properties were studied by UV-Vis absorption and PL spectroscopy. These quantum dots were then employed in clad-modified fiber optic gas sensors operating at room temperature. Sensor response towards various VOCs, including acetone, ethanol, methanol, and ammonia, were evaluated. Ethanol displayed remarkable sensitivity and selectivity among the other, with a response of 104 ×103 Counts/kPa at 25 °C for 500 ppm. Rapid response and recovery times of 48 and 55 seconds, respectively, further highlights the sensor’s performance. These results establish Sm2O3 quantum dots as a promising and highly effective material for ethanol sensing.

Laser-based synthesis of silver nanoparticles embedded in cellulose paper for catalytic reduction of azo dyes and SERS sensing of pesticides

In this study, highly reactive bare silver nanoparticles (Ag NPs) are synthesized using the Pulsed Laser Ablation in Liquid (PLAL) technique. Ag NPs are then coated on the filter paper using the dip coating method. This process converts filter paper into a versatile substrate for catalysis and surface-enhanced Raman Spectroscopy (SERS) based sensing. The successful synthesis of spherical Ag NPs and their effective embedding into the filter paper was confirmed using UV–visible absorption spectroscopy, scanning electron microscopy (SEM), and Energy Dispersive x-ray analysis (EDX). SEM images revealed that the Ag NPs were embedded in the filter paper and attached to the cellulose fibers. The use of Ag NPs embedded filter paper as a catalyst substrate for the reduction of both cationic and anionic dyes demonstrated that higher concentrations of Ag NPs on the filter paper resulted in a faster reduction. In particular, filter paper impregnated with 52 μg of Ag NPs demonstrated a complete reduction of methylene blue and methyl orange in less than a minute and 4 min, respectively. To demonstrate the practical sensing capability of the Ag NPs embedded filter paper, it was utilized as a SERS substrate. This enabled the detection of trace levels of Rhodamine 6G (R6G) and the pesticide molecule chlorpyrifos, demonstrating its potential real-world applications.

Synthesis of Ultrawide Band Gap TeO2 Nanoparticles by Pulsed Laser Ablation in Liquids: Top Ablation versus Bottom Ablation.

Ultrawide band gap (UWBG) semiconductors are the future components of electronic devices due to their large energy band gap (>3.2 eV). In this article, spherical TeO2 nanoparticles, with sizes around ∼39 ± 12 and ∼29 ± 6 nm, were successfully synthesized by irradiating a pure tellurium target, totally submerged in ethanol, using a "Top-ablation" or "Bottom-ablation" synthesis protocol, respectively. Mostly, α-TeO2 nanoparticles were created (>95%) with only a small amount of γ-TeO2 nanoparticles being produced (<5%). Both colloids exhibited a ζ-potential larger than |30 mV|, indicating a stable colloidal solution. The energy band gaps of the TeO2 nanoparticles synthesized by the Top-ablation and Bottom-ablation synthesis protocols were determined to be around 5.3 and 5.8 eV, respectively. Finally, TeO2 UWBG nanoparticles were successfully synthesized using either a Top-ablation or Bottom-ablation synthesis protocol. The main advantage of the Bottom-ablation synthesis protocol is its ability to obtain smaller nanoparticles compared to that of the Top-ablation synthesis protocol.

Experimental Parametric Investigation of Nanosecond Laser-Induced Surface Graphitization of Nano-Crystalline Diamond.

While nano-crystalline diamond (NCD) is a promising engineering composite material for its unique mechanical properties, achieving the ultrahigh surface quality of NCD-based components through conventional grinding and polishing is challenging due to its exceptional hardness and brittleness. In the present work, we experimentally investigate the nanosecond laser ablation-induced graphitization characteristics of NCD, which provides a critical pretreatment method of NCD for realizing its superlative surface finish. Specifically, systematic experimental investigations of the nanosecond pulsed laser ablation of NCD are carried out, in which the characteristics of graphitization are qualitatively characterized by the Raman spectroscopy detection of the ablated area of the microhole and microgroove. Subsequently, the influence of laser processing parameters on the degree and morphological characteristics of graphitization is evaluated based on experimental data and related interpretation, from which optimized parameters for maximizing the graphitization of NCD are then identified. The findings reported in the current work provide guidance for promoting the machinability of NCD via laser irradiation-induced surface modification.

Pulsed Laser Ablation Characteristics of Light-Absorbing Mask Layer Based on Coating Thicknesses under Laser Lift-Off Patterning Process.

Thin transparent oxide layers are typically patterned for use in electronic products including semiconductors, displays, and solar cells for applications such as transparent electrodes, insulating films, and encapsulation films. Conventional patterning methods have traditionally been used in photolithography and lift-off processes. Photolithography employs the wet development process, which has disadvantages such as potential undercut effects, swelling, chemical contamination, and high process costs. On the other hand, laser ablation, which has the advantages of high accuracy, high speed, a noncontact nature, and selective processing, can be used to pattern thin films. However, absorption in transparent oxide films is usually low. In this study, experiments were conducted to determine the ablation characteristics of mask layers. The factors affecting ablation, including beam radii, fluences, overlap ratios, and coating thicknesses, were examined; and the parameters characteristic of residue-free ablation, namely the ablation threshold, minimum fluence, and minimum ablation linewidth, were also examined. The experimental results revealed that the beam radius was an important parameter in determining the resolutions of transparent films and substrates.

Elucidating the Role of Electron Transfer in the Photoluminescence of MoS2 Quantum Dots Synthesized by fs-Pulse Ablation.

Herein, MoS2 quantum dots (QDs) with controlled optical, structural, and electronic properties are synthesized using the femtosecond pulsed laser ablation in liquid (fs-PLAL) technique by varying the pulse width, ablation power, and ablation time to harness the potential for next-generation optoelectronics and quantum technology. Furthermore, this work elucidates key aspects of the mechanisms underlying the near-UV and blue emissions the accompanying large Stokes shift, and the consequent change in sample color with laser exposure parameters pertaining to MoS2 QDs. Through spectroscopic analysis, including UV-visible absorption, photoluminescence, and Raman spectroscopy, we successfully unraveled the mechanisms for the change in optoelectronic properties of MoS2 QDs with laser parameters. We realize that the occurrence of a secondary phase, specifically MoO3-x, is responsible for the significant Stokes shift and blue emission observed in this QD system. The primary factor influencing these activities is the electron transfer observed between these two phases, as validated by excitation-dependent photoluminescence and XPS and Raman spectroscopies.

Isotherm and kinetics study of Ni(II) ions adsorption from wastewater using carbon nanotubes decorated with ZnO nanoparticles

A zinc oxide/carbon nanotube hybrid (ZnO/MWCNT) was synthesized utilizing a straightforward precipitation technique based on the physical approach of pulsed laser ablation. Various techniques were employed to investigate the composition, morphology and optical of the synthesized nanocomposite. The techniques employed were X-ray diffraction, Raman spectroscopy, transmission electron microscopy, FT-IR and thermal gravimetric analysis (TGA) to confirm the compete decoration to be applicable for removal Ni(II) ions in an aqueous solution. ZnO have a hexagonal wurtzite structure connected to hexagonal graphite of MWCNT from XRD. The interaction between ZnO and CNTs resulted in a reduction in the domain of sp2 bonds, according to Raman. From TGA, we can attribute the reduction in thermal analysis to the oxidation of surface hydroxyl functional groups (-OH), the evaporation of surface solvent and the presence of ZnO’s inorganic oxide structure compared to pristine MWCNT. These findings confirmed that adding ZnO NPs to MWCNT caused more structural flaws and surface disorder, even though the structure of the CNTs stayed the same. We then investigated numerous factors affecting the extraction of Ni(II) ions, including pH, duration of extraction, amount of nanosorbent used and circumstances. We observed the optimal conditions at room temperature, pH of 5.9, nanoadsorbent dosage of 0.2 g/L and contact time of 1 h. Atomic absorption spectrometry easily monitored the kinetics of this reaction. The Langmuir, Freundlich and Redlich–Peterson isotherm models explain the mechanism underlying the adsorption equilibrium isotherm. Furthermore, regeneration experiments revealed that the adsorbent still maintained a high adsorption capacity after six cycles, demonstrating remarkable potential for use in environmentally friendly applications.

Investigation of ablation efficiency and properties of silicon carbide nanoparticles synthesised using pulsed laser ablation in liquid

This study optimised the synthesis and ablation efficiency of 3C silicon carbide (SiC) nanoparticles (NPs) using nanosecond pulsed laser ablation in liquid for electronic and biomedical applications. Various process parameters, including laser fluence, scanning speed, and ablation time, were systematically varied to assess their impact on ablation efficiency and NP properties. Statistical analysis identified optimal conditions: a 15 min ablation time, 0.5 m/s scanning speed, and 7.5 J/cm² laser fluence with the maximum mass productivity of 1.196 mg.h−1W−1. Characterisation techniques, including UV-Vis, Dynamic Light Scattering (DLS), FESEM with EDX, FTSEM, and XRD, confirmed that higher laser fluence, scanning speed, and ablation time increased colloid concentrations without altering NP shape or size. XRD analysis verified the phase composition as 3C SiC, with DLS showing smaller NP sizes than image analysis. The results also suggested that increasing the NP size decreased the optical band gap. A direct correlation was found between ablated mass and colloid concentration.

Fe(Se,Te) Thin Films Deposited through Pulsed Laser Ablation from Spark Plasma Sintered Targets.

Iron-based superconductors are under study for their potential for high-field applications due to their excellent superconducting properties such as low structural anisotropy, large upper critical fields and low field dependence of the critical current density. Between them, Fe(Se,Te) is simple to be synthesized and can be fabricated as a coated conductor through laser ablation on simple metallic templates. In order to make all the steps simple and fast, we have applied the spark plasma sintering technique to synthesize bulk Fe(Se,Te) to obtain quite dense polycrystals in a very short time. The resulting polycrystals are very well connected and show excellent superconducting properties, with a critical temperature onset of about 16 K. In addition, when used as targets for pulsed laser ablation, good thin films are obtained with a critical current density above 105 A cm-2 up to 16 T.

High-performance Ag-TiO2 nanoparticle composite catalyst synthesized by pulsed laser ablation in liquid: properties, mechanism and preparation studies

Precious metal doping can effectively improves the catalytic performance of TiO2. In this study, pulsed laser ablation in liquid (PLAL) is employed to integrate preparation with doping and control composite nanoparticle products by adjusting the laser action time to synthesise Ag-TiO2 composite nanoparticles with high catalytic performance. The generation and evolution of Ag-TiO2 nanoparticles are investigated by analysing particle size, microscopic morphology, crystalline phase, and other characteristics. The generation and doped-morphology evolution of composite nanoparticles are simulated based on thermodynamics, and the optimisation of Ag-doped structure on the composite nanomaterials is investigated based on density functional theory. The effect of Ag-TiO2 structural properties on its performance is examined under different catalytic conditions to determine optimal degradation conditions. In this study, the effect of laser ablation time on the doped structure during PLAL is analysed, which is of further research significance in exploring the structural evolution law of laser and composite nanoparticles, multi-variate catalytic performance testing, reduction of photogenerated carrier complexation rate, and expansion of its spectral absorption range, thereby providing the basis for practical production.

Optimization of carbon-based thin film microextraction supports for simultaneous detection of heavy metals using LIBS

One of the most versatile and effective methods to improve LIBS analysis of liquids is Thin Film Microextraction (TFME).This approach generally uses carbon-based adsorbent films to extract analytes from a liquid sample and bind them into a solid matrix, which is ideal for LIBS. In a previous work, we demonstrated the feasibility of TFME supports based on graphene prepared by Pulsed Laser Ablation in Liquid (PLAL) for LIBS analysis.In this paper, we optimized the preparation of such supports for the analysis of heavy metals in aqueous samples (i.e. chromium, lead and nickel), by analyzing both standard solutions and real samples. The feasibility of coupling TFME with NELIBS approach was also exploited. The procedure was applied to the analysis of both mineral water and well water samples.We obtained a standardized procedure for the extraction of three analytes (Pb, Cr and Ni) and estimated LOD values in spiked mineral water of the order of 0.6 mg/L for LIBS and 0.2 mg/L for NELIBS.

On the van der Waals Heteroepitaxy and Hydroxylation/Oxidation States of Au@Muscovite by Pulsed Laser Ablation in Water and Recovery in Aqueous KOH Solution

On the van der Waals Heteroepitaxy and Hydroxylation/Oxidation States of Au@Muscovite by Pulsed Laser Ablation in Water and Recovery in Aqueous KOH Solution