Pulsed Laser Ablation In Liquid Research Articles

Laser - Produced Functional Surfaces of Silicon and Quartz

Fiber laser of 1064 nm wavelength was employed for micro/nano machining process of silicon and quartz substrates. The experimental data reveal formation of silicon nanoparticles by pulse laser ablation in liquid. Various characterization techniques were used such as UV-Visible absorption, SEM morphology to examine silicon nanoparticles. Moreover, generation of microbeams from micro lens array was created by direct writing of fiber laser on quartz. Theoretical calculations using COMSOL software were adopted to estimate the surface temperature distribution at silicon and quartz surface and underneath. It is found that maximum temperature of about (4600 K) and (2400 K) for silicon and quartz respectively when 15 W laser power, 127 ns pulse duration, 30 KHz frequency and 100 mm/sec laser speed was used. Potential applications of silicon nanoparticles and microbeams array in optoelectronics and biological imaging can be conducted due to the controllable laser micro/nano machining process.

Structural optical and morphological properties of copper oxide nanoparticles ablated using pulsed laser ablation in liquid

Structural optical and morphological properties of copper oxide nanoparticles ablated using pulsed laser ablation in liquid

Laser Ablated Citrate-Stabilized Silver Nanoparticles Display Size and Concentration Dependant Biological Effects

Silver nanoparticles (AgNPs) have been recognized for widespread biological applications due to their antimicrobial and anti-inflammatory effect, especially in dentistry and for wound healing. Many features determine their beneficial or toxic potential, such as their synthesis type, size, morphology, coating, and concentration. Most synthesis types rely on the use of synthetic chemicals, which contributes to their toxicity. We present an environmentally friendly method for “green” synthesis of AgNPs from the silver target by pulsed laser ablation in liquid (PLAL) using citrate as the stabilizing agent. Since AgNPs already have many dental applications, we examined their antibacterial effect against supragingival biofilm-forming bacteria and bacterial strains known to cause resistant dental infections. Their impact on human fibroblast cells’ cytotoxicity, proliferation (measured by XTT and Ki-67 immunofluorescence), pro/antioxidant balance, and lipid peroxidation (measured by PAB and LPP) was evaluated. AgNPs1 (21 nm) and AgNPs2 (15 nm) spherical nanoparticles with good overall stability were obtained. The highest tested dose of smaller nanoparticles (AgNPs2) displays not only an effective antibacterial effect against the tested oral bacteria strains but also a pro-oxidant and cytotoxic effect on fibroblast cells. Lower doses do not affect bacterial survival but increase the cell proliferation and metabolic activity and show an antioxidative effect, suggesting that different concentrations display a substantially opposite effect. Compared to larger AgNPs1, smaller AgNPs2 possess more potent biological effects, indicating that size plays a pivotal role in their activity. Such opposite outcomes could be important for their medical application, and high concentrations could be used for the inhibition of dental biofilm formation and resistant dental infections as well as proliferative conditions, while low doses could be beneficial in the treatment of atrophic and inflammatory disorders. Finally, we showed that silver-targeted PLAL, using citrate as a stabilizing agent, produces biologically potent nanoparticles that could have many applications depending on their size and concentration.

Synthesis and characterizations of zinc peroxide by pulsed laser ablation in liquid (PLAL) and zinc oxide nanoparticles by simple and low-temperature heating treatment

Zinc peroxide (ZnO2) and zinc oxide (ZnO) nanoparticles have interesting properties. Thus, they have the potential to be applied as optoelectronic devices. Pulsed laser ablation in liquid (PLAL) method is one of the top-down synthesis methods which have several advantages, such as its low cost, no need for a vacuum environment, and relatively fast synthesizing nanoparticle materials. Nd-YAG laser with a second harmonic generator was used as the laser beam source for the experiment. The mixture of zinc powder, deionized water, and hydrogen peroxide (H2O2) as oxidizing agent was treated by the PLAL method. Heating treatment was applied to the samples. X-ray diffraction, UV-vis spectrophotometry, and Fourier Transform Infrared (FTIR) were applied as the sample characterization methods. X-Ray diffraction characterizations confirmed ZnO2 nanocrystal and ZnO nanocrystal, which were synthesized from ZnO2 through an annealing process. From UV-vis spectrophotometry, the values of 4.57 eV and 3.33 eV were obtained as the bandgap energy for ZnO2 and ZnO, respectively. FTIR spectra shows absorption peaks for ZnO2 and ZnO.

Synthesis of Antibacterial Copper Oxide Nanoparticles by Pulsed Laser Ablation in Liquids: Potential Application against Foodborne Pathogens.

Spherical copper oxide nanoparticles (CuO/Cu2O NPs) were synthesized by pulsed laser ablation in liquids (PLAL). The copper target was totally submerged in deionized (DI) water and irradiated by an infrared laser beam at 1064 nm for 30 min. The NPs were then characterized by dynamic light scattering (DLS) and atomic emission spectroscopy (AES) to determine their size distribution and concentration, respectively. The phases of copper oxide were identified by Raman spectroscopy. Then, the antibacterial activity of CuO/Cu2O NPs against foodborne pathogens, such as Salmonella enterica subsp. enterica serotype Typhimurium DT7, Escherichia coli O157:H7, Shigella sonnei ATCC 9290, Yersinia enterocolitica ATCC 27729, Vibrio parahaemolyticus ATCC 49398, Bacillus cereus ATCC 11778, and Listeria monocytogenes EGD, was tested. At a 3 ppm concentration, the CuO/Cu2O NPs exhibited an outstanding antimicrobial effect by killing most bacteria after 5 h incubation at 25 °C. Field emission scanning electron microscope (FESEM) confirmed that the CuO/Cu2O NPs destructed the bacterial cell wall.

Quantum dots decorated photoanodes in bioelectrochemical fuel cells: Enhanced electricity generation using green algae.

The power performance of the bio-electrochemical fuel cells (BEFCs) depends mainly on the energy harvesting ability of the anode material. The anode materials with low bandgap energy and high electrochemical stability are highly desirable in the BEFCs. To address this issue, a novel anode is designed using indium tin oxide (ITO) modified by chromium oxide quantum dots (CQDs). The CQDs were synthesized using facile and advanced pulsed laser ablation in liquid (PLAL) technique. The combination of ITO and CQDs improved the optical properties of the photoanode by exhibiting a broad range of absorption in the visible to UV region. A systematic study has been performed to optimize the amount of CQDs and green Algae (Alg) film grown using the drop casting method. Chlorophyll (a, b, and total) content of algal cultures (with different concentrations) were optimized to investigate the power generation performance of each cell. The BEFC cell (ITO/Alg10/Cr3//Carbon) with optimized amounts of Alg and CQDs demonstrated enhanced photocurrent generation of 120 mA cm-2 at a photo-generated potential of 24.6 V m-2 . The same device exhibited a maximum power density of 7 W m-2 under continuous light illumination. The device also maintained 98% of its initial performance after 30 repeated cycles of light on-off measurements.

Ex situ and in situ functionalized Yb/Fe nanoparticles obtained by scanning pulsed laser ablation in liquids: A route to obtain biofunctionalized multiplatform contrast agents for MRI and CT imaging

Two distinct strategies were used to improve the colloidal properties of hybrid Yb/Fe oxide NPs previously prepared by the pulsed liquid laser ablation process for use as a contrast agent in medical imaging.First, an exhaustive optimization process of the laser ablation synthesis parameters was carried out to reduce the hydrodynamic diameters of the Yb/Fe NPs. The hydrodynamic size was successfully reduced to <200 nm, thereby decreasing the polydispertivity index.Second, ex situ and in situ functionalization processes using glutathione, cysteamine, or polyethylenimine as capping agents have been developed to increase their colloidal stability at physiological pH values. Transmission electron microscopy, dynamic light scattering, Z-potential measurements, and Fourier Transform Infrared spectroscopy were used to examine the structure, morphology, colloidal and surface properties of Yb/Fe NPs.Colloidal stability of the Yb/Fe NPs as well as the linkage mechanism of functionalization have been studied extensively. This last parameter provides a critical information for subsequently bioconjugations in biomedical applications. Additionally, the biocompatibility of the Yb/Fe NPs was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) experiments. These results indicate more appropriate colloidal characteristics and higher biocompatibility for ex situ-functionalized Yb/Fe NPs, especially when the capping agent is glutathione. Additionally, these Yb/Fe NPs show good magnetic resonance imaging and X-ray computerized tomography imaging abilities, thereby indicating promising potential as dual contrast agents.

Manifolding active sites and in situ/operando electrochemical-Raman spectroscopic studies of single-metal nanoparticle-decorated CuO nanorods in furfural biomass valorization to H2 and 2-furoic acid

Here, CuO nanorods fabricated via pulsed laser ablation in liquids were decorated with Ir, Pd, and Ru NPs (loading ∼7 wt%) through pulsed laser irradiation in the liquids process. The resulting NPs-decorated CuO nanorods were characterized spectroscopically and employed as multifunctional electrocatalysts in OER, HER, and the furfural oxidation reactions (FOR). Ir–CuO nanorods afford the lowest overpotential of ∼345 mV (HER) and 414 mV (OER) at 10 mA cm−2, provide the highest 2-furoic acid yield (∼10.85 mM) with 64.9% selectivity, and the best Faradaic efficiency ∼72.7% in 2 h of FOR at 1.58 V (vs. RHE). In situ electrochemical-Raman analysis of the Ir–CuO detects the formation of the crucial intermediates, such as Cu(III)-oxide, Cu(OH)2, and Irx(OH)y, on the electrode–electrolyte surface, which act as a promoter for HER and OER. The Ir–CuO || Ir–CuO in a coupled HER and FOR-electrolyzer operates at ∼200 mV lower voltage, compared with the conventional electrolyzer and embodies the dual advantage of energy-saving H2 and 2-furoic acid production.

Manifolding surface sites of compositional CoPd alloys via pulsed laser for hydrazine oxidation-assisted energy-saving electrolyzer: Activity origin and mechanism discovery

Energy-driven overall water splitting (OWS) for renewable hydrogen generation is critical for carbon neutrality. However, the OWS electrolyzer efficiency is significantly affected by the kinetically sluggish anodic oxygen evolution reaction (OER). An efficient approach is proposed to promote energy-saving hydrogen production by using a composition-dependent multifunctional CoPd alloy via pulsed laser ablation in liquids, where the OER is replaced with the hydrazine oxidation reaction (HzOR). The CoPd alloy improves N2H4 chemisorption onto the surface via dative bonding between the lone pair electrons of N and the empty 5 s orbital of Pd and 3d of low spin Co. The optimal Co1Pd9 alloy sample demonstrates excellent hydrogen evolution reaction and HzOR with the lowest overpotentials of 0.224 and 0.329 V at 10 mA/cm2 in 1.0-M KOH and 1.0-M KOH/0.5-M N2H4, correspondingly. An in situ/operando Raman study reveals that metal active site and structural transformation occurred during the oxidation (M*-O) and reduction (M*-H) reactions under an alkaline medium. Besides, the overall hydrazine splitting performed using the Co1Pd9 ‖ Co1Pd9 electrolyzer requires a cell voltage of ∼ 0.228 V only at 10 mA/cm2 with remarkable electrochemical and structural stability over 10 h, which is significantly lower than that of the traditional OWS electrolyzer (∼1.837 V). This study demonstrates the practical use of CoPd alloys in direct N2H4 fuel cells to produce both H2 fuel and electrical energy.

Antibacterial activity of silver nanoparticles created by one step nanosecond Nd: YAG laser ablation in water

The pulsed laser ablation in liquid (PLAL) technique was used to successfully synthesise silver nanoparticles (Ag NPs). With the goal of controlling their size, a laser wavelength of 1064 nm was focused on the Ag bulk target immersed in distilled water in a glass vessel with different laser fluences. The effect of laser fluence, and thus Ag NPs concentration on the bacterial pathogenic was investigated. While the Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) patterns confirm the presence of Ag NPs, UV–vis spectrophotometry revealed a significant absorption peak at around 405 nm, which is attributed to the obtained Ag NPs’ characteristic surface plasmon resonance (SPR) peak. The SPR peak shifted towards a shorter wavelength as the laser fluence was increased, indicating that the Ag NPs have reduced in size. The transmission electron microscopy and size distribution images of Ag NPs clearly showed the effects of laser fluence on size reduction of Ag NPs. Bacteria activity was effectively inhibited by the Ag NPs which are found to be more effective against Gram-negative (Escherichia coli) than Gram-positive strains (Streptococcus aureus). PLAL has proven to be an effective method for controlling the size of NPs, which can be used in a variety of applications.

Mechanistic insights into ZIF-67-derived Ir-doped Co3O4@N-doped carbon hybrids as efficient electrocatalysts for overall water splitting using in situ Raman spectroscopy

Developing highly active bifunctional electrocatalytic nanomaterials toward overall water splitting (OWS) is required to address the energy crisis via manufacturing clean hydrogen (H2) fuel. Herein, we demonstrate the rational synthesis of a bifunctional electrocatalyst based on an Ir-doped Co3O4-anchored N-doped carbon (Ir-Co3O4@NC) hybrid for the OWS. Zeolitic imidazolate framework-67 (ZIF-67) polyhedrons was synthesized by a novel pulsed laser ablation in liquid (PLAL) technique. Subsequently, ZIF-67 polyhedrons were employed as a self-template and cobalt precursor to develop the Ir-Co3O4@NC hybrid using ion exchange and calcination approaches. Owing to the availability of more active metal sites, effective charge transport, huge surface area, and good conductivity, the Ir-Co3O4@NC hybrid displayed excellent bifunctional catalytic activity toward the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The in situ Raman spectroscopy results demonstrated the creation of Co(OH)2 species for the HER and CoOOH and Ir-O species for the OER as active intermediates at the electrode–electrolyte interfaces. As a result, the fabricated alkaline water electrolyzer with the Ir-Co3O4@NC∥Ir-Co3O4@NC exhibited a low cell potential of 1.62 V at 10 mA cm−2 and superior catalytic durability. Our work paves the way for the practical applications of effective bifunctional electrocatalysts for hydrogen production.

Synthesis AgO Nanoparticles by Nd:Yag Laser with Different Pulse Energies

One technique used to prepare nanoparticles material is Pulsed Laser Ablation in Liquid (PLAL), Silver Oxide nanoparticles (AgO) were prepared by using this technique, where silver target was submerged in ultra-pure water (UPW) at room temperature after that Nd:Yag laser which characteristics by 1064 nm wavelength, Q-switched, and 6ns pulse duration was used to irradiated silver target. This preparation method was used to study the effects of laser irradiation on Nanoparticles synthesized by used varying laser pulse energy 1000 mJ, 500 mJ, and 100 mJ, with 500 pulses each time on the particle size. Nanoparticles are characterized using XRD, SEM, AFM, and UV-Visible spectroscopy. All the structural peaks determined by the XRD test can be indexed as face-centered cubic (FCC) type, the stronger crystalline orientation is located in the (111) plane. The nanoscale particles have an almost spherical shape as inferred from the SEM images. In (1000) mJ laser pulse energy the best smallest particle size was produced. According to AFM results of all films, the particle size 32.45nm, 64.3nm, and 67.86nm respectively for 1000 mJ, 500 mJ, and 100 mJ , the surface roughness affected and increased as increase the laser energy because the increase particle size and aggregation of partials. UV-Visible spectroscopy measured the absorbance of the silver nanoparticle prepared which is increased as increase pulsed laser ablation energy at wavelength 440 nm.

High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation

Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts.

Laser-assisted synthesis of metallic composite nanostructures in aqueous solutions

The method of pulsed laser ablation in liquids (PLAL) is applied for synthesis of composite nanostructures on the basis of TiOx and ZnO combined with noble metals like Au, Pt and Pd. The metallic plate immersed in water is laser ablated by nanosecond Nd:YAG pulsed laser irradiation. Its fundamental wavelength and the fourth harmonic are used, respectively, to produce and to modify the morphology and structure of the nano-objects. The synthesis procedure consists of two consecutive steps: laser ablation of the selected metal targets followed by unfocused laser beam irradiation of the initial colloids of nanostructures. The phase composition, structural and the shape and size morphological features were assessed by analytical method – transmission electron microscopy (TEM) in its main modes – Bright Field TEM (BF TEM), High Resolution TEM (HRTEM) and Selected Area Electron Diffraction (SAED). Formation of bimetallic polycrystalline alloys and Pt/Ti(TixOy) and Pd/Ti(TixOy) core-shell nanoparticles was founded.

Pulsed laser ablation production of Ni/NiO nano electrocatalysts for oxygen evolution reaction

Efficient and sustainable materials are requested to overcome the actual major issues related to green energy production. Ni/NiO nanoparticles (NPs, 2–4 nm in size) produced by Pulsed Laser Ablation in Liquid (PLAL) are reported as highly efficient and stable electrocatalysts for oxygen evolution reaction (OER) in water splitting applications. Ni/NiO NPs dispersions are obtained by ablating a Ni target immersed in deionized water with an Nd:YAG nanosecond pulsed laser. NPs size and density were driven by laser energy fluence (ranging from 8 to 10 J cm−2) and shown to have an impact on OER performance. Ni/NiO NPs were characterized by scanning and transmission electron microscopy, x-ray diffraction, photoemission spectroscopy, and Rutherford back-scattering spectrometry. By drop-casting onto graphene paper, anode electrodes were fabricated for electrochemical water splitting in alkaline electrolytes. The extrinsic and intrinsic catalytic performances for OER have been quantified, achieving an overpotential of 308 mV (at a current density of 10 mA cm−2) and unprecedented mass activity of more than 16 A mg−1, using NPs synthesized with the highest and lowest laser energy fluence, respectively. The impact of NPs’ size and density on OER performances has been clarified, opening the way for PLAL synthesis as a promising technique for highly efficient nano-electrocatalysts production.

Synthesis of ZnO/C Nanocomposites via Liquid-Assisted Laser Ablation in an Applied Electric Field for Supercapacitor Applications

The formation of nonspherical anisotropic nanoparticles having a large surface area by pulsed laser ablation in liquids (PLAL) still remains a challenge. In this work, to expand the capabilities of the PLAL technique, an approach was developed based on pulsed laser ablation in liquids with an external voltage applied to the target. This approach allowed shape-controlled preparation of nonspherical ZnO/C composite nanomaterials providing additional possibilities for tuning of the particles’ morphology that was found to depend on the applied voltage and polarity. The positive polarity on the Zn target allowed obtaining nanodisk structures, whereas application of negative polarity to the target enabled the formation of flower-like nanostructures proven by scanning (SEM) and transmission electron microscopy (TEM) studies. The optimal conditions for the nanoflower formation were found with the voltage set to be 200 V. A time-resolved imaging technique was applied to study plasma propagation evolution and lifetime that allows suggesting the mechanisms of nanoflower formation. Furthermore, utilizing the developed approach in a carbon nanoparticle colloid, sponge-like composites were obtained having a developed surface that showed promising capacitance and charge storage behavior in preliminary electrochemical tests. The ZnO/C composite structures were evidenced by SEM and TEM studies as well as by EDX mapping, X-ray diffraction, Raman, infrared, and optical absorption spectroscopy measurements. In addition, the production of particles in the presence of an electric field leads to the deposition of the formed nanostructures on the cathode surface that can serve as a tool for assembling the resulting particles into ordered structures for subsequent supercapacitor applications.

A novel method for ZnO@NiO core–shell nanoparticle synthesis using pulse laser ablation in liquid and plasma jet techniques

Given their versatile nature and wide range of possible applications, core–shell nanoparticles (NPs) have received considerable attention. This paper proposes a novel method for synthesizing ZnO@NiO core–shell nanoparticles using a hybrid technique. The characterization demonstrates the successful formation of ZnO@NiO core–shell nanoparticles, which have an average crystal size of 13.059 nm. The results indicate that the prepared NPs have excellent antibacterial activity against both Gram-negative and Gram-positive bacteria. This behavior is primarily caused by the accumulation of ZnO@NiO NPs on the bacteria's surface, which results in cytotoxic bacteria and a relatively increased ZnO, resulting in cell death. Moreover, the use of a ZnO@NiO core–shell material will prevent the bacteria from nourishing themselves in the culture medium, among many other reasons. Finally, the PLAL is an easily scalable, cost-effective, and environmentally friendly method for the synthesis of NPs, and the prepared core–shell NPs could be used in other biological applications such as drug delivery, cancer treatment, and further biomedical functionalization.

Synthesis and characterization of polyethyleneimine/silk fibroin/gold nanoparticle nanocomposites: Potential application as a gene carrier in breast cancer cell lines

There is a need in advancing the design of non-viral gene carriers, thus herein using the pulsed laser ablation in liquid (PLAL) technique, polyethyleneimine-capped gold nanoparticles (PEI-AuNPs) were synthesized and then combined with Bombyx mori silk fibroin (SF) to form the nanocomposites (PEI-SF-AuNPs). After the characterization analyses were carried out, PEI-AuNPs and PEI-SF-AuNPs were tested for their in vitro biocompatibility in MCF-7 and MDA-MB231 breast cancer cells. Finally, the transfection capability of the selected group was observed. PEI capping enabled the cationic modification of the AuNP surface and SF reduced the surface charge (from 35 to 4 mV). PEI-AuNPs were highly monodispersed in shape and size (8–9 nm). The nanoparticle group synthesized in 5% (w/v) PEI concentration (PEI-AuNP5) had increased cytotoxicity as compared to the group synthesized in 1% (w/v) PEI concentration (PEI-AuNP1), but the conjugation of SF with PEI-AuNPs alleviated this cytotoxic tendency significantly. The group (PEI-AuNP1) with the most negligible cytotoxicity proved to be successful in the transfection of siRNA analog, i.e., siGLO green transfection indicator. Overall, the PEI-AuNP1 nanocomposites could be suggested as potent siRNA carriers due to the above beneficial properties in gene-based breast cancer therapies.

Tailored CuCl2 nanoparticles for glutamine and ammonia biochemical sensing applications

In this study, CuCl2 nanoparticles (NPs) synthesised via pulsed laser ablation in liquid (PLAL) were successfully employed to simultaneously detect glutamine and ammonia, with a limit of detection of 20 nM and up to 1500 ppm, respectively. These NPs hold potential for non-invasive diagnosis and monitoring of various health conditions using urine and sweat samples. The sensing mechanism relied on the plasmon peaks of CuCl2 NPs in the UV range (at 300, 363, and 423 nm), which were used to correlate the levels of glutamine and ammonia concentration with the absorbance. Quasi-spherical CuO and pyramidal CuCl2 NPs were synthesised through laser ablation of Cu powder in liquid IPA and IPA-HCl, respectively. CuCl2 NPs displayed higher ablation efficiency, higher optical absorbance (20-fold), and an 8400-fold increase in colloidal conductivity (0.0005 vs 4.2 mS/cm) compared to CuO NPs. The NP size distribution ranged broadly from 10 nm to less than 100 nm. XPS analysis revealed that ablation in pure IPA resulted in oxidized Cu NPs, while ablation in IPA-HCl liquid medium (12 nM HCl) led to the formation of a combination of metallic copper and CuCl2 NPs that were more conductive and had higher optical absorbance than their oxidized counterparts.

Atomistic modeling of pulsed laser ablation in liquid: spatially and time-resolved maps of transient nonequilibrium states and channels of nanoparticle formation

Atomistic modeling of pulsed laser ablation in liquid: spatially and time-resolved maps of transient nonequilibrium states and channels of nanoparticle formation