Laser Ablation In Liquid Media Research Articles

A COMPARATIVE STUDY OF ALUMINUM OXIDE NANOPARTICLES SYNTHESIZED IN PLASMA DISCHARGE UNDER ULTRASONIC CAVITATION AND BY LASER ABLATION FOR CREATION OF COMPOSITE MATERIALS

In this work, aluminum oxide nanoparticles were fabricated by two physical methods: laser ablation in liquid medium and plasma discharge under the action of intensive ultrasonic cavitation. Dynamic light scattering, scanning electron microscopy, and electrokinetic potential measurements were employed to comparatively examine the nanoparticles obtained by both methods. It was found that the synthesized particles had spherical shapes with a size range of about 50-70 nm and relatively narrow particle size distributions and were stable to aggregation and sedimentation. The electrokinetic potential values of the pure particles and the effects of the presence of water-soluble polymer polyethylene glycol were used to examine the surface properties of the nanoparticles. This study demonstrates the effect of ultrasonic action on particle surface activity.

Surface-Modified Carbon Nanotubes with Ultrathin Co3O4 Layer for Enhanced Oxygen Evolution Reaction.

Alkaline water electrolysis is a vital technology for sustainable and efficient hydrogen production. However, the oxygen evolution reaction (OER) at the anode suffers from sluggish kinetics, requiring overpotential. Precious metal-based electrocatalysts are commonly used but face limitations in cost and availability. Carbon nanostructures, such as carbon nanotubes (CNTs), offer promising alternatives due to their abundant active sites and efficient charge-transfer properties. Surface modification of CNTs through techniques such as pulsed laser ablation in liquid media (PLAL) can enhance their catalytic performance. In this study, we investigate the role of surface-modified carbon (SMC) as a support to increase the active sites of transition metal-based electrocatalysts and its impact on electrocatalytic performance for the OER. We focus on Co3O4@SMC heterostructures, where an ultrathin layer of Co3O4 is deposited onto SMCs using a combination of PLAL and atomic layer deposition. A comparative analysis with aggregated Co3O4 and Co3O4@pristine CNTs reveals the superior OER performance of Co3O4@SMC. The optimized Co3O4@SMC exhibits a 25.6% reduction in overpotential, a lower Tafel slope, and a significantly higher turnover frequency (TOF) in alkaline water splitting. The experimental results, combined with density functional theory (DFT) calculations, indicate that these improvements can be attributed to the high electrocatalytic activity of Co3O4 as active sites achieved through the homogeneous distribution on SMCs. The experimental methodology, morphology, composition, and their correlation with activity and stability of Co3O4@SMC for the OER in alkaline media are discussed in detail. This study contributes to the understanding of SMC-based heterostructures and their potential for enhancing electrocatalytic performance in alkaline water electrolysis.

Synthesis and Characterization of Bi4Ti3O12 Nanoparticles Obtained via Pulsed Laser Ablation in Liquids

Bismuth titanate (BTO) nanoparticles were obtained by pulsed laser ablation in liquid media (PLAL). Distilled water, ethanol, isopropanol, and acetone were used as media for laser ablation experiments, in which the colloidal solutions were obtained. Laser ablation was carried out using the second harmonic and fundamental wavelength of a pulsed Nd:YAG laser (532 nm and 1064 nm, respectively) with laser fluences of 25 and 12 mJ/cm2, respectively. Transmission electron microscopy was utilized for morphological characterization. BTO nanoparticles obtained have spherical shapes with orthorhombic structure and the average size distribution depended on the liquid media nature. In alcohols, BTO NPs were spherical with a carbon layer around them. X-ray diffraction, UV-Vis absorption spectra, and X-ray photoelectron spectroscopy were used to confirm the structural, optical, and elemental properties of the ablated products. The presented results show that PLAL is a viable technique for the synthesis of high-quality BTO nanoparticles with enhanced optical properties for possible applications in photocatalysis.

Femtosecond laser-mediated preparation of HfNbTaTiZr refractory high-entropy alloy nanoparticles for photothermal therapy applications: Influence of solvent and fluence

Nanoparticles (NPs) have become popular photothermal therapy (PTT) photosensitizers because they can be targeted to cancer tissues and deliver a chemotherapeutic medication. Pulsed laser ablation in liquid media (PLAL) can produce stable colloidal NPs without any stabilizing agents. The stability, size distribution, and morphology of the produced colloids are influenced by the nature of NPs, laser parameters such as laser power, laser frequency repetition, ablation rate, and the specific ionic effects from the solvent. In this work, HfNbTaTiZr refractory high entropy alloy (RHEA) NPs were prepared by PLAL method in different solvents, including distilled water, ethanol, and n-hexane. The experiments were performed by irradiating a HfNbTaTiZr target with a femtosecond laser outputting 120-fs pulse at varying levels of ablation fluence (0.1, 0.16, 0.23 mJ/cm2). The elemental and structural characteristics of the prepared HfNbTaTiZr NPs were elucidated by using several advanced analytical techniques. The XRD pattern of NPs revealed that the liquid medium significantly affects the type of crystallized phases and the surface composition. The surface composition was studied by XPS, indicating that the fabricated NPs were oxidized. SEM and TEM analysis have evidenced the generation of NPs with an average diameter of less than 50 nm. The results revealed that the higher ablation fluence resulted in the formation of NPs with a larger average diameter. The highest intrinsic photothermal conversion efficiency and 12 °C time-dependent solvent heating produced in ethanol at 640 nm irradiation after 20 min were demonstrated.

Improvement of glass ionomer restoration by adding ZnO nanoparticles prepared by laser in (Vitro study)

The technique of pulsed laser ablation in liquid media was successfully used to prepare zinc oxide ZnO nanoparticles NPs to enhance glass ionomer GI restorative. The synthesized ZnO NPs were confirmed using UV–Visible spectroscopy, XRD, and TEM. The absorption spectra revealed that the absorbance intensity of the prepared ZnO NPs increased as the number of laser pulses increased, with an absorbance peak at 230 nm due to quantum confinement. The crystalline nature of NPs with hexagonal structure is revealed by XRD analysis. The TEM images demonstrated the nanorod shape with a length of about 3.33 nm and there were spherical nanoparticles ranging from 5 nm to 30 nm. ZnO NPs with and without GI were tested for antibacterial activity against Streptococcus mutans bacteria, which shows slight improvement after adding ZnO NPs to glass ionomer as a result of containing effective ingredients in its composition. The agar well diffusion method results revealed that ZnO with GI had a higher antibacterial activity compared with pure ZnO NPs. Finally, the compressive strength test illustrated significant enhancement of up to 50% associated with the ZnO NP's concentration increase.

Synthesis and characterization of selenium nanoparticles obtained by femtosecond pulsed laser ablation in liquid media

Synthesis and characterization of selenium nanoparticles obtained by femtosecond pulsed laser ablation in liquid media

Luminescent carbon nanostructures synthesized by ultrasound-assisted laser ablation in liquid media

Luminescent carbon nanostructures synthesized by ultrasound-assisted laser ablation in liquid media

Third order optical nonlinear properties of gold (Au) nanoparticles synthesized by green laser ablation in bio-based Poly(ε-caprolactone) solution

In this work, Poly(ε-caprolactone) (PCL) and gold(Au) nanocomposite has been fabricated by pulsed laser ablation (PLA) of gold target dipped in PCL solution performed by aid of Ti: Sapphire femtosecond (fs) laser to form nanoparticles (NPs). The prepared sample have been investigated by various analyses techniques to evaluate their elemental composition, optical and morphological properties. UV–Vis absorbance spectrum was recorded over a range of wavelength from 300 nm to 900 nm and it has shown a typical Au surface plasmon effect in visible region and PCL:Au nanocomposite absorbed more photons in UV region compared with that in infrared region. Photon energy band gap value has been calculated as 3.5 eV by means of absorbance spectrum. Transmission Electron Microscopy (TEM) and TEM-Energy dispersive X-Ray (TEM-EDX) images proved that the size of Au NPs appears to vary from 5 nm to 50 nm range produced using fs laser ablation in liquid medium. Fourier Transform Infrared Spectroscopy (FT-IR) analysis have been carried out for PCL and PCL:Au composite which they were characterized in over a frequency region from 400 to 4000 cm−1 and characteristic peaks were seen at 2905, 2805, 1755 and 1205 cm−1. Furthermore, nonlinear optical properties of PCL:Au composite was investigated using fs laser z-scan technique changing laser intensity between 9.50 × 1011 W/cm2 and 2.37 × 1012 W/cm2. The nonlinear absorption coefficient (β), nonlinear refractive indexes (n2) have been computed to be ∼10−10 - 10−11 cm2/W and ∼10−16 - 10−19 cm/W, respectively. Third-order susceptibilities have also revealed for PCL:Au nanocomposite as 10−13–10−14 esu. The obtained green synthesized PCL:Au composite material can be applicable in the optoelectronic field as optical limiting materials.

Removal of methylene blue dye from aqueous solution using carbon nanotubes decorated by nickel oxide nanoparticles via pulsed laser ablation method

A simple, green, inexpensive and eco-friendly method of pulsed laser ablation in liquid media (PLAL) technique was used to synthesize different nanocomposites to be applied as accelerators in the reducing of harmful organic chemical compounds and eliminating biological hazards in remediation applications. Herein, PLAL technique was used to prepare NiO-MWCNTs nanocomposites in just one step for the catalytic degradation of methylene blue dye in the presence of reducing agent. Then, different characterization techniques were used to confirm the formation of the nanocomposite structure. TEM results showed that NiO NPs are spherical in shape, with an average size of 20 nm with a face centered cubic (FCC) structure based on XRD diffractograms, while XPS data revealed that the tubular structure of carbon nanotubes had been successfully functionalized then decorated with NiO NPs, whereas the Raman spectra exhibited that the structural defects of MWCNTs were increased after embedding with NiO NPs. Following that, under ideal conditions, the produced nanocomposite displayed excellent catalytic activity in the reductive degradation of 70.22% from the investigated methylene blue dyes in just 10 min. As a result, NiO-MWCNTs nanocomposites are an appealing choice for wastewater treatment due to their excellent catalytic reduction capability and economic feasibility.

Synthesis of multi-walled carbon nanotubes decorated with silver metallic nanoparticles as a catalytic degradable material via pulsed laser ablation in liquid media

Multi-walled carbon nanotube decorated with silver nanoparticles (MWCNTs/Ag nanocomposite) was prepared with clean, simple, and one-pot method as catalytic degradable material for nitro compounds and dyes. This method based on using Nd:YAG (1064 nm, 10 Hz, and 7 ns) for the ablation of silver plate immersed in functionalized MWCNTs solution. The prepared nanocomposite material was investigated by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and the thermal gravimetric analysis (TGA). The prepared sample was studied as a catalyst for the reduction of hazardous 4-nitrophenol, methyl orange, and methylene blue. This study represents that Ag-MWCNTs nanocomposite has a promising catalytic rate constant for the reduction of 4-NP, MO, and MB with values 0.0055 s −1 , 0.017 s −1 , and 0.0098 s −1 , respectively. This research is considered as a powerful, feasible, environmentally safe, and cost-effective route for the production of a powerful catalyst for the degradation of hazardous materials and dyes. • Ag-MWCNTs nanocomposite was synthesized by ablation of Ag plate in f -MWCNTs. • The as-prepared nanocomposite has a good catalytic activity. • The produced nanocomposite has high distribution without using any surfactant. • The nanocomposites were synthesized via simple one-pot green method. • The resulted nanocomposites were characterized by XRD, Raman, XPS, TEM, and TGA.

Novel laser-assisted method for synthesis of SnO2/MWCNTs nanocomposite for water treatment from Cu (II)

A novel multiwalled carbon nanotubes/SnO2 nanocomposite was synthesized by the aid of pulsed laser ablation in liquid media with the assistant of sonication process. In this method, SnO2 was firstly prepared by the laser ablation of tin target immersed in ultra-pure water via Nd:YAG laser, followed by high power ultrasonic irradiation of f-MWCNTs to obtain multiwalled carbon nanotubes/SnO2 nanocomposite to be applied in sorption of Cu(II) for water treatment. The adsorbent was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray, transmission electron microscope (TEM), Raman spectroscopy, X-ray photoelectron spectroscopic analysis (XPS), and Fourier transform infrared spectroscopy (FTIR). The influence of several variables such as pH, contact time, and Cu(II) concentration at room temperature was studied in batch experiments. The adsorption efficiency was evaluated to estimate the nature of the sorption process toward the removal of Cu (II) ions for water treatment.

Generation of nanomaterials in dopant-containing liquid via pulsed laser ablation

Nanoparticles of ZnS doped with Cu were prepared by means of pulsed laser ablation in liquid medium containing Cu ions. Nanosecond pulsed laser was focused on Zn target immersed in mercaptoethanol with copper nitrate dissolved as a source of Cu ions. X-ray diffraction and X-ray photoelectron spectroscopy confirmed formation of wurtzite ZnS structures as the main product, while up to ~5% of Zn atoms were substituted by Cu when ≤1.0 mM Cu(NO3)2 in mercaproethanol was used as liquid medium. Elemental mapping revealed that dopant Cu atoms were uniformly distributed in the produced nanoparticles. Photoluminescence recorded from the doped nanomaterial exhibited an additional green emission, indicating the presence of interband states resulted from doping with Cu2+. Compared with undoped ZnS nanoparticles, their Cu-doped counterparts demonstrated more efficient photocatalytic behavior toward the decomposition of methylene blue (as model organic compound), which is believed to be caused either by more efficient light absorption extended into the visible region or by the carriers based on the Cu2+ state. The present study demonstrates that the technique used has the capacity of producing doped nanomaterials in one step by incorporating dopants from the liquid phase, which may be promising for preparing novel unique nanomaterials with complex composition.

The effect of laser fluence for enhancing the antibacterial activity of NiO nanoparticles by pulsed laser ablation in liquid media

Pulsed laser ablation in liquid media technique was successfully used to synthesize nickel oxide (NiO) in nanoscale with different particle sizes by varying the laser fluence per pulse for enhancing the antibacterial activity against several pathogens. This process was carried by nanosecond infrared Nd:YAG laser. The produced samples were investigated by X-ray diffraction, UV–vis absorption spectroscopy, Zeta potential, and Transmission electron microscope. Its structural investigation via X-ray diffraction showed that the formation of the face center cubic structure of NiO. Its optical investigation via UV–vis absorption spectroscopy showed the varying of its energy bandgap values as the used laser fluence changed, whereas the Zeta potential showed the stability of the prepared samples for 24 h. Its morphological study via transmission electron microscope showed the varying of their particle sizes as the used laser fluence changed. After that, the antibacterial activity of the prepared samples was investigated against different bacterial strains (Streptococcus aureus, Bacillus subtilis, Escherichia coli, and Candida albicans). It showed the efficiency of NiO nanoparticles was enhanced by decreasing their particle size and it has high effectivity against the gram-negative strains rather than the gram-positive. This behavior of the antibacterial activity was investigated and supported by MIC technique, the time required for killing the growth of bacterial strains, and the expected mechanism.

Study of thermal conductivity of synthesized Al2O3-water nanofluid by pulsed laser ablation in liquid

In the present study, Aluminum oxide (Al2O3) nanoparticles dispersed water based nanofluids were prepared via laser ablation in liquid method. Al2O3 nanoparticles were synthesized in deionized water using a nanosecond Nd-YAG pulsed laser operating at 1064 nm. The structural, optical and morphological characterizations of the produced nanofluids were performed. Thermal properties of the prepared samples were evaluated through thermal conductivity measurements which were carried out at various nanoparticles concentration and at temperatures ranging from 25 °C to 45 °C. Morphological analysis by transmission electron microscopy revealed spherically shaped Al2O3 nanoparticles with an average size of 9 nm. Moreover, the results indicated that the thermal conductivity of Al2O3-water nanofluid was improved as compared to the pure water. The increase in temperature and nanoparticles concentration leads to higher thermal conductivity of nanofluids. It was found that the thermal conductivity enhancement was around 8.6% at nanoparticles volume fraction of 0.7 vol% and temperature of 45 °C. This work proved the possibilities of fabricating Al2O3-water nanofluid with enhanced thermal conductivity via laser ablation in liquid medium without the use of hazardous chemicals and vacuum conditions. Therefore, the synthesized nanofluids have great potential to be applied in medium temperature applications.

Gold nanoparticles size distribution by pulsed laser varying the wavelength

In this work the influence of the wavelength variation of a pulsed laser on the size distribution of gold nanoparticles, synthesized by laser ablation in liquid medium, was determined, since this technique is the most used due to its simplicity as it is not developed under strict conditions of temperature, pressure, agitation, etc. Three different wavelengths were used: (i) 532 nm, (ii) 355 nm and (iii) 266 nm, due to equipment restrictions. The distributions and sizes of nanoparticles were studied by dynamic light scattering, scanning electron microscopy and atomic force microscopy. In addition, it is shown that the spectra of the gold region determine the chemical state of the nanoparticle. The results showed that the smallest particle size was obtained with the wavelength of 266 nm with a size of 9.6 nm, while for the other wavelengths; sizes of 55.4 nm and 77.3 nm were obtained respectively. Thus, smallest average diameter of gold nanoparticles was obtained with smallest wavelength.

Ablation energy, water volume and ablation time: Gold nanoparticles obtained through by pulsed laser ablation in liquid

It was studied the production of gold nanoparticles from a gold target by pulsed laser ablation in liquid medium. This technique allows replacing conventional methods of preparing nanoparticles without the need for precursors, where gold is used in its metallic state. Experimental tests were performed to determine the appropriate synthesis conditions to achieve small particle sizes. The variables studied were water volume, ablation time and ablation energy. Gold nanoparticles with spherical geometry, in metallic, and nanocrystalline state were obtained without the need to use precursors and stabilizers. Ablation energy is the most influential variable on the particle size, because it was observed that when is increased the ablation energy is generate greater particle sizes.

Effect of confined geometry on the size distribution of nanoparticles produced by laser ablation in liquid medium

An effective method has been proposed for controlling the size distributions of metallic nanoparticles produced through laser ablation in liquid by employing physical boundaries in the vicinity of the ablation site. An Nd:YAG laser (1064 nm, FWHM 6 ns) has been used to ablate the copper target immersed in two different liquid medium, water and isopropyl alcohol. Water and isopropyl alcohol have been chosen because of the significant differences in their densities while the optical properties are nearly comparable. To demonstrate the efficacy of the method, experiments have been conducted in both the configurations, that is, with and without confining boundaries. To ascertain the observed effect, select experiments have also been carried out with gold as the target material to ensure that the size distribution is not influenced because of oxide-layer formation. The size of the particles were estimated from the SEM images and analysing these images using an indigenously developed code. It has been observed that there are significant differences in the size distributions in the cases of nanoparticles produced with and without confining boundaries. For any given medium, a consistent increase in the mean size of the nanoparticles produced with the targets fitted with physical boundary has been observed as compared to those produced with flat targets. The observed trend has been attributed to the plausible role of the shock wave reflection from the physical boundaries, which alters the plasma parameters. Reflected shock wave–plasma interactions prolonging the thermalisation time of the plasma plume in confined geometry facilitate the particle growth, resulting in the formation of bigger particles. The proposed method, which can be applied to any metallic target, is one of the greener methods for producing nanoparticles and is also relatively simple and cost effective.

Multi walled carbon nanotube decorated cadmium oxide nanoparticles via pulsed laser ablation in liquid media

A simple synthesis method to produce multi walled carbon nanotubes (MWCNTs) decorated with metal oxide nanoparticles (e.g., cadmium oxide (CdO)) has been described by pulsed laser ablation of Cadmium sheets immersed in precursor solution from functionalized MWCNTs. The as-prepared of decoration composites of MWCNTs with CdO nanoparticles were characterized by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, transmission electron microscopy, scanning electron microscopy, Energy dispersive X-ray spectroscopy, and X-ray diffraction, which revealed that these decorations of CdO nanoparticles were uniformly distributed on the surface of MWCNTs with diameter about 22 nm. Also, the optical properties of MWCNTs were successfully enhanced after decoration via metal oxide nanoparticles. This work could be used to decorate MWCNTs via different metals oxides via pulsed laser ablation in liquid media technique to produce interesting new properties of MWCNTs composite.

Impact of ablation time on Cu oxide nanoparticle green synthesis via pulsed laser ablation in liquid media

Large-scale commercial production of nanoparticles via efficient, economical, and environmentally friendly methods is a challenging endeavour. The laser ablation method being a green and potential route of nanoparticles synthesis can be exploited to achieve this end. In this work, we report the ablation of a copper target submerged in distilled water by pulsed Nd:YAG laser. The influence of ablation time on the structure and optical properties of grown copper oxide nanoparticles are studied. Such nanoparticle composition and structure is determined by X-ray diffraction (XRD), Fourier transform infrared, and Raman analyses. Results from transmission electron microscopy images established that synthesised nanoparticles are a spherical shape with average sizes of 24–37 nm. Fluorescence spectra revealed the enhancement of nanoparticle concentration and reduction in the sizes with increasing ablation time, where the optimum ablation time is demonstrated to be 60 min. Photoluminescence spectra exhibited a prominent visible peak (green), which blueshifted from 542 to 537 nm, confirming the shrinkage of copper oxide particle size at higher ablation time. The XRD pattern showed that the prepared nanoparticles possess a single phase of monocline cupric oxide nanostructure.

Structural and optical properties of TiO2–Ge nanoparticles prepared through laser ablation in liquid medium

Quantum dot (QD) composite nanoparticles of titania germanium (TiO2–Ge) were fabricated by pulsed laser ablation of composite targets of TiO2–Ge immersed in deionized water. The single phase crystallanity, lattice parameters, and the evaluation of crystallite size of nanoparticles was investigated by X-ray diffraction (XRD). The morphology of the samples was analyzed through scanning electron microscopic studies. The average particle size calculated through XRD and measured through scanning electron microscope is in the range from 18 to 29 nm and are in agreement with each other. Compositional study was carried out through electron dispersive X-ray analysis showing that the ablation rate of Ge is smaller than TiO2. Optical properties were measured by UV–visible transmission spectra and Raman spectroscopy. The band gap of composite particles varies from the UV to the visible range by varying concentration of Ge QDs. This work shows that pulsed laser ablation in liquid media is an easy approach to synthesize ultrafine, contamination-free nanosized material, which is difficult to produce by other conventional methods.