Laser Ablation In Liquid Environment Research Articles

Efficient Oxygen Evolution Reaction Catalyzed by Ni/NiO Nanoparticles Produced by Pulsed Laser Ablation in Liquid Environment

Electrochemical water‐splitting, sustained by renewable energy, is aimed at green H2 production. Efficient and sustainable electrocatalysts are required for a proper energy transition. Oxygen evolution reaction (OER) in alkaline electrolyte can be pursued by using earth‐abundant elements‐based catalysts, such as Ni oxyhydroxides. A proper optimization of intrinsic properties and synthesis procedure is still needed. Herein, the synthesis of Ni/NiO nanoparticles (NPs) through a physical and green technique, pulsed laser ablation in liquid (PLAL), is presented. Ablating a Ni target in deionized water, at different ablation times, leads to NP dispersions used for realization of OER electrode onto graphene paper. Ion‐beam analysis of catalysts amount and homogeneity of NP‐based electrode is performed for the electrode optimization in terms of electrochemical performances. An overpotential at 10 mA cm−2 of 306 mV is achieved for 40 μg cm−2 of catalyst, while lowering the catalyst amount to 8 μg cm−2, unprecedented turnover frequency of 0.20 s−1 and mass activity of ≈1.3 A mg−1 are reached. These data show that Ni/NiO NPs produced by PLAL are highly effective for OER in alkaline media and encourage the use of PLAL as a green and efficient technique for electrocatalyst production.

Low temperature detection of nitric oxide by CuO nanoparticles synthesized by pulsed laser ablation

Fast, selective and low-cost sensors for nitric oxide (NO) detection are highly desirable due to the harmful effects of this gas. Low temperature NO detection is challenging, requiring selective and effective catalytic processes. Here, we present an experimentally based CuO-NO interaction model in the 50–400 °C temperature range and a promising NO chemoresistive sensing device working at 50 °C based on CuO nanoparticles (NPs) produced by pulsed laser ablation in liquid environment (PLAL). Ligand-free Cu/Cu2O nanostructures produced by PLAL were converted into 35 ± 12 nm CuO NPs by 400 °C annealing, and analysed by X-Ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray techniques. The chemoresistive sensor is produced by drop-casting the CuO NPs suspension onto an interdigitated electrode and tested in a flow-controlled test chamber. Below 250 °C, oxidation behavior is recorded, while above 350 °C reduction takes place, with a peculiar transient regime observed at 300 °C. A full model of CuO-NO interaction is proposed, based on Langmuir adsorption theory and kinetics barriers extracted by response curves in the 50–400 °C temperature range. A peculiar catalytic activity of CuO NPs emerges in combination with oxygen species absorbed at different temperature, leading to effective NO detection. The ease and scalability of CuO NPs production by PLAL and the reported fast and selective NO sensor working at 50 °C open promising routes towards exploitation for massive and affordable harmful gas detection.

Laser assisted synthesis of WS2 nanorods by pulsed laser ablation in liquid environment

Two dimensional (2D) materials are widely attracting the interest of researchers due to their unique crystal structure and diverse properties. In the present work, tungsten disulfide (WS[Formula: see text] nanorods were synthesized by a simple method of pulsed laser ablation in liquid (PLAL) environment. The prepared WS2 are analyzed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV-visible spectroscopy (UV-vis) and Raman spectroscopy to confirm the surface morphology, phase and structure. A possible growth mechanism of WS2 is proposed. This study indicates new door for the preparation of 2D materials with specific morphology.

Zeta Potential of Ag, Cu, ZnO, CdO and Sn Nanoparticles Prepared by Pulse Laser Ablation in Liquid Environment

Metal nanoparticles (NPs) of silver (Ag), copper (Cu), zinc oxide (ZnO), cadmium oxide (CdO) and tin (Sn) were synthesized by laser ablation of a solid target in de-ionized water (DI). X-ray diffraction patterns showed the formation of AgO, Ag, Cu, ZnO, CdO, and Sn NPs. Absorbance spectrum of the produced nanoparticles was measured by UV-Vis spectrophotometer which showed that Ag and CdO NPs shifted to the short wavelength (blue shift), indicating the formation of NPs with smaller sizes, whereas CuO showed the formation two peaks. ZnO and Sn NPs shifted to the long wavelength (red shift) which indicates the formation NPs with larger size. Zeta potential results proved that ZnO nanoparticles were more stable (-26.53mV) than the other metal nanoparticles, while CdO nanoparticles had more aggregation (-16.65mV).

Bismuth-based metal–organic framework prepared by pulsed laser ablation method in liquid

Metal organic framework (MOF) is an important class of highly porous hybrid materials with its unique structures and properties. A bismuth-based MOF was prepared by pulsed laser ablation in liquid environment as a physical bottom-up method for the first time. The experiment involved the ablation of a bismuth target in a solvents with the fundamental wavelength of a ns pulsed Nd:YAG laser. Materials include bismuth target for preparation of Bi3+ ion as a connector center, benzene-1,3,5-tricarboxylic acid (BTC) as a bridging ligand, and methanol and dimethylformamide as a solvent. We studied the effects of laser fluence and concentration of BTC in the ablation environment on the properties of bismuth-based MOF structure. The MOF was characterized by Fourier transform infrared spectroscopy for determination of functional groups, Ultraviolet–Visible (UV–Vis) spectrophotometer for evaluation of optical properties, X-ray diffraction for investigation of crystal structure, field emission scanning electron microscope, and transmission electron microscope for presentation of morphology and size of produced nanostructures. Based on the results, laser ablation is a capable, clean, and simple candidate method for synthesizing different kinds of MOF.

Experimental and Theoretical Investigations of Beam Deformation Produced by Thermal Lens Effect on a Gaussian Laser Beam in Ethanol

In this paper, influence of thermal lens on propagation of a Gaussian beam through ethanol was investigated experimentally and numerically. The influence of laser power on the thermal lens strength and laser beam characteristics at far field was analyzed. The experimental and numerical results show that a Gaussian laser beam is deformed because of thermal lensing effect. According to these results at enough high laser power a doughnut beam is formed. The deformed beam characteristics i.e. the beam diameter, the size of central dark region of the doughnut beam, and the ratio of peak to valley values were also analyzed. The results show that the numerical and experimental results are in good agreement. The results of this investigation can be very useful for experiments involved to pulse laser ablation in liquid environment (PLAL).

Multi-walled carbon nanotubes /boron oxide composite using plasmonic Ag nanoparticles: Synthesis and SERS characterization

In this work, by applying a straightforward and easy technique B2O3 doped MWCNTs synthesized using laser ablation in liquid environment (LALE) method. The plasmonc properties of Ag NPs prepared via Lee-Meisel technique was used to prepare high quality substrates for Surface – enhanced Raman scattering (SERS) measurements The size of Ag NPs was acknowledged by UV/Vis/NIR absorption spectroscopy and SEM imaging (<50 nm). A rather powerful SERS signal was created due to the plasmonic effect and the presence of Ag NPs. Furthermore, SERS spectra were collected in all the synthesized samples. The concentration level down to 10−4 molar (M) of boron oxide (B2O3) doped samples were detected. The recorded data reveals that an enhancement factor (EF) SERS factor of about 105 can be easily achieved applying this method.

One-pot synthesis of nanostructured CdS, CuS, and SnS by pulsed laser ablation in liquid environment and their antimicrobial activity

We describe here a generic method for producing high-quality metal sulfide nanoparticles of a controllable and narrow size distribution in the nano-metric range. Metal sulfide nanostructures (CdS, CuS, and SnS) are synthesized by using nanosecond pulsed laser ablation in a liquid solution containing sulfur precursor in just one step (one-pot versatile synthesis method). The optical properties have been studied using UV–Visible spectroscopy showing the main characteristic transition peaks of metal sulfides. Transmission electron microscope (TEM) shows a uniform Smaller-sized and nearly spherical nanocrystals exhibited a cross lattice pattern. The structure study by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) reveal the purity and the spherical crystalline structure of all the prepared nano metal sulfides. After that, the antibacterial activity has been examined against four types of bacteria and unicellular fungi by using agar plate diffusion methods followed by studying the required time for killing. The tested microorganisms strain is showing that CuS nanoparticles have the highest antimicrobial activity.

Cadmium oxide/TEMPO-oxidized cellulose nanocomposites produced by pulsed laser ablation in liquid environment: Synthesis, characterization, and antimicrobial activity

The TEMPO-oxidized cellulose nanofibers (TOCN) was prepared from bagasse pulp, followed by embedding with cadmium oxide nanostructure via pulsed infrared laser ablation of cadmium sheets immersed in TOCN solution in just one step. The TOCN before and after embedding was studied via different characterization techniques as X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), UV–visible spectroscopy, Transmission electron microscope (TEM), and Energy dispersive X-ray (EDX). These techniques confirmed that TOCN were successfully prepared and the CdO nanostructure is well embedded with nanofiber structure of the prepared TOCN with dimension equaled about 59 nm. Then the prepared sample were studied their antibacterial activity againstmany pathogenic microorganisms. The minimal inhibition concentration (MIC) is emphasized that the prepared nanocomposite has broad spectrum antimicrobial activity with low MIC values which recorded 1.56 μg/ml for gram negative bacteria, less than 1.56 for gram positive bacterial and 0.19 μg/ml for Candida albican.

Effect of different hardness and melting point of the metallic surfaces on structural and optical properties of synthesized nanoparticles

The relations between macroscopic and microscopic characteristics of materials are of utmost importance for synthesis of multi-atomic structures with advanced properties. We analyze the influence of pulse duration, pulse energy and temperature of liquid on the process of formation of nanoparticles (NPs) of the metals (In, Sn, Zn and W) with different hardness and melting temperature by laser ablation in liquid environment. Composition, morphology dynamics and properties of nanoparticle suspensions are studied using TEM analysis and Z-scan technique. The nonlinear optical properties of NPs are analyzed at 800 and 400 nm using 60 fs and 200 ps pulses. We show that pulse energy have little influence on the formation, morphology and size of NPs during ablation of low hardness and melting point metal (In). However, pulse duration plays a very important role during the formation of NPs, especially the ultra-short pulse has a positive effect on the preparation of NPs with smaller particle size. In addition, the temperature of liquid environment influences the formation of NPs and their nonlinear optical properties.

Production of meloxicam suspension using pulsed laser ablation in liquid (PLAL) technique

Organic particles in the micrometer/nanometer size range can find applications in various fields. Unfortunately their production is not a straightforward task for a number of materials. In the present work the production of meloxicam particles in the micrometer range was aimed with the help of pulsed laser ablation in liquid environment (PLAL). Targets pressed from crystalline meloxicam powder were placed in distilled water and irradiated with a focused beam of a frequency doubled (532 nm) nanosecond Nd:YAG laser at 4.2–9.4 J cm−2 fluence. Morphological investigation showed that the produced suspension contained particles in the ~100 nm to 10 µm size range (1.0–2.0 µm on average), which is about 10 times smaller than the size of the initial material. FTIR spectroscopic investigations demonstrated that the chemical composition was preserved, while x-ray diffraction and calorimetric measurements indicated partial amorphization of meloxicam during the process. The overall results suggest that the particles are mostly produced by the fragmentation of the pressed target by the recoil forces induced by the laser pulse. Long period sedimentation tests of the suspension combined with UV–vis spectroscopic analysis showed that by the method of PLAL a greater fraction of the poorly water soluble meloxicam could be dispersed and dissolved in water in a pharmaceutically preferred formation than by simple dissolution of it.

Synthesis of cadmium oxide nanoparticles by pulsed laser ablation in liquid environment

Colloidal spherical nanoparticles of cadmium oxide (CdO) have been prepared by using Nd:YAG pulsed laser ablation [1064nm, 7ns, 10Hz, and 80mJ] of cadmium sheets target immersed on deionized water. The optical properties of prepared CdO nanoparticles were investigated by using UV–vis spectrophotometer. The morphology and structure were analyzed by scanning electron microscopy, transmission electron microscope, Energy dispersive spectroscopy, and X-ray diffraction. The structure of CdO nanoparticles is confirmed to be crystalline and has hexagonal structure. The morphology of CdO nanoparticles is nano spherical particles with diameter approximately 47nm. Also, the stability of prepared nanoparticles is studied using successive electronic spectra up to 300min. Each spectrum shows very similar behavior and it could be seen there are no shift in the position of the wavelength maximum.

Investigation of factors affecting the synthesis of nano-cadmium sulfide by pulsed laser ablation in liquid environment

Pulsed laser ablation in a liquid medium is a promising technique as compared to the other synthetic methods to synthesize different materials in nanoscale form. The laser parameters (e.g., wavelength, pulse width, fluence, and repetition frequency) and liquid medium (e.g., aqueous/nonaqueous liquid or solution with surfactant) were tightly controlled during and after the ablation process. By optimizing these parameters, the particle size and distribution of materials can be adjusted. The UV–vis absorption spectra and weight changes of targets were used for the characterization and comparison of products.

Synthesis of Nano-Cadmium Sulfide by Pulsed Laser Ablation in Liquid Environment

A pulsed laser-assisted in liquid environment method has been developed successfully to synthesize size-tunable (5–12 nm) and different shapes (sphere, rod, rope) of nano II–VI semiconductor (cadmium sulfide). This method can be carried out in two ways; the first one is the top-down technique, which has been discussed in publications in the last few decades, and the other one is the bottom-up technique, which appears for the first time in this paper. X-ray diffraction, ultraviolet-visible spectroscopy, and transmission electron microscopy confirm that the nanoparticles are crystalline. The methods lead to the production of nanomaterials, which are important for photonics and biosensing applications. Both synthesized methods can be applied in all materials because of their ability to ablate almost all kinds of materials due to the ultrahigh energy density and control over the growth process by manipulating the process parameters such as intensity, wavelength, and so on.

Cu/Ag-based bifunctional nanoparticles obtained by one-pot laser-assisted galvanic replacement

We have prepared, for the first time, stable and uncapped Ag/Cu-based bifunctional nanoparticles (NPs) (BFNPs) in water, by combining ps laser ablation in liquid environment and galvanic replacement. The particles were obtained in a single step by 1,064 nm irradiation of a Cu target in water solutions of AgNO3 or AgNO2. Under proper salt concentration and irradiation conditions, the laser beam activates formation of deep orange colloids, which are positively charged and stable for weeks. High resolution transmission electron microscopy (HRTEM) analysis showed a predominance of composite crystalline nanostructures with size in the 1–15 nm range and consisting of fcc Ag and fcc Cu (or its oxides). While CuO tenorite crystalline phase was detected by HRTEM, X-ray photoelectron spectroscopy analysis permitted to observe also the Cu(I) oxidation state of Cu, being the Cu(I)/Cu(II) ratio different in the samples obtained in AgNO3 or AgNO2 baths. Functionalization with organic ligands and subsequent Raman tests demonstrated the SERS activity of the BFNPs and the existence of different complexing surface sites.

Band gap tuning of ZnO nanoparticles via Mg doping by femtosecond laser ablation in liquid environment

We use multiphoton IR femtosecond laser ablation to induce non-thermal non-equilibrium conditions of the nanoparticle growth in liquids. Modifications of the electronic properties of ZnO NP were achieved by Mg ion doping of targets prepared from mixtures of Zn and Mg acetylacetonates. The nanoparticle sizes were 3–20nm depending on the ablation conditions. X-ray fluorescence indicates that stoichiometric ablation and incorporation of Mg in nanocrystalline ZnO occurs. HRTEM observations show that nanoparticles retain their wurtzite structure, while at high Mg concentrations we detect the MgO rich domains. Exciton emissions exhibit relatively narrow bands with progressive and controlled blue shifts up to 184meV. The exciton energy correlates to band edge absorption indicating strong modification of the NP band gaps. Stabilisation of the exciton blue shift is observed at high Mg concentration. It is accompanied by the formation of structure defects and ZnO/MgO phase separation within the nanoparticles.

Dendrimer-Capped Nanoparticles Prepared by Picosecond Laser Ablation in Liquid Environment

Fifth generation ethylendiamine-core poly(amidoamine) (PAMAM G5) is presented as an efficient capping agent for the preparation of metal and semiconductor nanoparticles by ps laser ablation in water. In particular, we describe results obtained with the fundamental, second and third harmonic of a ps Nd:YAG laser and the influence of laser wavelength and pulse energy on gold particle production and subsequent photofragmentation. In this framework, the role of the dendrimer and, in particular, its interactions with gold clusters and cations are accounted.

A novel method of nanocrystal fabrication based on laser ablation in liquid environment

Metal nanoparticles can be prepared by a novel technique that consists of the laser ablation of a solid target immersed in a water solution of a metal salt. Silicon was chosen as the most adequate target to synthesize silver and gold nanoparticles from a water solution of either AgNO 3 or HAuCl 4. The influence of both the silver nitrate concentrations and the irradiation time of the Si target on the optical properties of the Au and Ag nanoparticles have been investigated. The crystalline nature of the metal nanoparticles has been determined by X-ray diffraction (XRD). Average size and particle size distribution have been measured by means of TEM. The absorbance spectra show the characteristic band of the surface resonant plasmon of silver and gold nanoparticles.

Generation of Ag nanospikes via laser ablation in liquid environment and their activity in SERS of organic molecules

The formation of dense arrays of nanospikes occurs under laser ablation of bulk silver immersed in liquids such as water or ethanol. The average height of spikes is 50 nm and their density on the target amounts to 1010 cm-2. This effect is observed with sufficiently short laser pulses. In particular, either a 350 ps or a 90 ps Nd:YAG lasers are used operating in their fundamental harmonics. These nanospikes are characterized by UV–visible reflection spectrometry and atomic force microscopy. The oscillations of electrons within Ag nanospikes results in a permanent coloration of the surface and a modification of the optical reflection spectra of the metal. Nanospikes show a peak of plasmon resonance around 380 nm, which shifts to the visible range upon oxidation in air. The initial spectrum may be restored by reduction of the oxidized Ag surface through processing in an ammonia aqueous solution. Scanning the laser beam along the metal surface allows its nanostructuring over extended areas (∼1 cm2). The nanostructured Ag surface shows enhanced Raman scattering of acridine molecules at a concentration of 10-5 M/l, whereas initial Ag target do not show any signal within the accuracy of measurements.

Recent Progress in Transition-Metal-Doped II–VI Mid-IR Lasers

Recent progress in transition metal (TM)-doped II-VI semiconductor materials (mainly Cr2+:ZnSe) makes them the sources of choice for laser when one needs a compact continuous wave (CW) system with tunability over 1.9-3.1 mum, output powers up to 2.7 W, and high (up to 70%) conversion efficiency. The unique combination of technological (low-cost ceramic material) and spectroscopic characteristics make these materials ideal candidates for new regimes of operation such as microchip and multiline lasing. This paper reviews these nontraditional Cr-doped middle-infrared (mid-IR) lasers as well as describes emerging Fe2+:ZnSe lasers having potential to operate at room temperature (RT) over the spectral range extended to 3.7-5.1 mum. In addition to being wideband semiconductors, effective RT mid-IR lasing TM-doped II-VI media also hold potential for direct electrical excitation. This paper shows the initial steps toward achieving this goal by studying Cr2+-Co2+- and-doped quantum dots. We have demonstrated a novel method of TM-doped II-VI quantum dots fabrication based on laser ablation in liquid environment. TM-doped II-VI quantum dots demonstrated strong mid-IR luminescence. It opens a new pathway for future optically and electrically pumped mid-IR lasers based on TM-doped quantum confined structures.