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Aspects of the Formation of Tin Oxide under Annealing of Nanopowders Obtained by Pulsed Laser Ablation of Metallic Tin in Aqueous Media
摘要： Nanocolloids, obtained by pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns, 150 mJ) of metallic Sn in distilled water and also in solutions of hydrogen peroxide and nitric acid, were dried and subjected to heat treatment at different temperatures up to 800°С. It has been shown that addition of H2O2 or HNO3 has an effect not only on the size characteristics and structure of the initial nanoparticles, but also on the process of formation and the final characteristics of SnO2 under annealing. By the method of powder x-ray diffraction it was established that in the case of pulsed laser ablation in water and in a solution of nitric acid, the initial particles contain the phase SnO, but for annealed sample obtained by ablation in HNO3, an intermediate orthorhombic phase of SnO2 is formed. Additional studies using Raman spectroscopy and thermal analysis made it possible to determine the presence of tin hydroxide in the initial samples and formation of intermediate forms of its oxides, SnOx, upon annealing.
关键词： pulsed laser ablation,nanoparticles,tin oxide,Raman spectra,crystal structure,annealing
更新于2025-09-12 10:27:22
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - THz Properties of Fe and Ti Oxides Nanoparticles Obtained by Pulsed Laser Ablation
摘要： We present Dielectric properties of Fe and Ti oxides nanoparticles (NPs) measured by THz-TDS. The NPs were obtained via ns pulsed laser ablation (PLA) of the metals in air and water and were annealed at different temperatures. In the paper, we exhibit the dependence of absorption spectra on NPs structure: from magnetite to hematite for Fe, and from anatase to rutile for Ti. The prospects for their use as materials for the THz photonics are discussed.
关键词： THz-TDS,Fe and Ti oxides nanoparticles,THz photonics,dielectric properties,pulsed laser ablation
更新于2025-09-12 10:27:22
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Laser‐Ablation Produced Cobalt‐Nickel Phosphate with High‐ValenceNickel Ions as Active Catalyst for Oxygen Evolution Reaction
摘要： Cost-effective, highly efficient and stable non-noble metal-based catalysts for oxygen evolution reaction (OER) are very crucial on energy storage and conversion. Here, we report an amorphous cobalt-nickel phosphate (CoNiPO4) containing considerable amount of high-valence Ni3+ specie as an efficient electrocatalyst for OER in alkaline solution. The catalyst was converted from Co-doped Ni2P through pulsed laser ablation in liquid (PLAL) and exhibits a large specific surface area of 162.5 m2/g and a low overpotential of 238 mV at 10 mA/cm2 with a Tafel slope of 46 mV/dec, being much lower than those of commercial RuO2 and IrO2. Our work demonstrates that PLAL is a powerful technology for generating amorphous CoNiPO4 with high-valence Ni3+, thus paving a new way towards highly effective OER catalysts.
关键词： OER,high valence state,cobalt-nickel phosphate,Pulsed laser ablation in liquid
更新于2025-09-12 10:27:22
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Effective size separation of laser-generated, surfactant-free nanoparticles by continuous centrifugation
摘要： High-power, nanosecond, pulsed-laser ablation in liquids enables the continuous synthesis of highly-pure colloidal nanoparticles (NPs) at an application-relevant scale. The gained mass-weighted particle size distribution is however often reported to be broad, requiring post treatment like centrifugation to remove undesired particle size fractions. To date, available centrifugation techniques are generally discontinuous, limiting the throughput and hindering economic upscaling. Hence, throughout this paper, a scalable, continuously operating centrifugation of laser-generated platinum nanoparticles in a tubular bowl centrifuge is reported for the first time. To that end, using a 121 W ns-laser, a continuous production of a colloidal suspension of NPs, yet with broad particle size distribution has been employed, yielding productivities of 1 - 2 g/h for gold, silver, and platinum. Subsequent downstream systematic study of relevant centrifugation parameters involved, effective size optimization and respective size sharpness parameters for a maximum Pt nanoparticle diameter of 10 nm are reported. The results of the experimental centrifugation of laser-generated Pt-NPs were in excellent agreement with the theoretically-calculated cut-off diameter. After centrifugation with optimized parameters, the polydispersity indices of the Pt-NPs size distributions were reduced by a factor of six and higher monodispersities were observed.
关键词： continuous process chain,tubular bowl centrifugation,contamination-free nanoparticle processing,Pt-NPs,pulsed laser ablation in liquids
更新于2025-09-12 10:27:22
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Photoluminescence mechanism of phosphorene quantum dots (PQDs) produced by pulsed laser ablation in liquids
摘要： Phosphorene quantum dots (PQDs) with high photoluminescence (PL) quantum yield were fabricated through pulsed laser ablation of black phosphorus in liquids. The PL emission showed excitation wavelength-independent features due to the suf?cient passivation by oxygen-containing substituents derived from the ablation-decomposed solvent molecules. There were four peaks in the PL pro?le showing a multi-frequency PL effect, which provided a viable route to investigate the PL mechanism via the detailed structures of the PL pro?le. The two peaks at shorter wavelengths were attributed to the intrinsic PL transitions. The two peaks at longer wavelengths were assigned to the transitions from the lowest unoccupied molecular orbital to the two-surface states. The positions of the four peaks are redshifted with increasing solvent molecular chain length due to the passivation effect. The intense, excitation wavelength-independent, multifrequency and blue-violet PL emissions indicate the potential application in semiconductor light sources.
关键词： semiconductor light sources,pulsed laser ablation,photoluminescence,phosphorene quantum dots
更新于2025-09-12 10:27:22
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The synthesis of carbon-based nanomaterials by pulsed laser ablation in water
摘要： Pulsed Laser Ablation in liquid (PLAL) is considered as a robust and simple technique for producing nanoparticles (NPs) using lasers. The carbon-based nanoparticles were fabricated via the PLAL approach by irradiating a graphite target with a pulsed Nd:YAG laser of wavelength 532 nm. The graphite target was immersed in distilled water and irradiated for 10 min. The pulse length, reputation rate, and ?uence were 6 ns, 10 Hz, and 0.4 J cm?2, respectively. The structural and physical properties of the synthesized NPs were investigated and analyzed using different characterization methods. For example, Transmission Electron Microscopy (TEM) images revealed diverse carbon nanostructures such as graphene nanosheets, nanospheres, nanospheres in the shape of a necklace, and nanotubes. The spectrum of Energy Dispersive X-Ray spectroscopy (EDX) con?rmed successful synthesis of high purity carbon nanostructures. Moreover, the result of X-Ray Diffraction (XRD) Spectroscopy indicated the presence of reduced Graphene Oxide (rGO) with a (002) plane and the absence of Graphene Oxide (GO). The transmission spectrum from Ultraviolet-Visible (UV–vis) analysis showed a strong trough at 266 nm which is attributed to the presence of carbon nanostructures. Furthermore, Fourier-Transform Infrared Spectroscopy (FTIR) analysis demonstrated the vibration bonds related to carbon. The nanostructures produced were semi-stable with little agglomeration as was inferred from the results of the Zeta Potential. Finally, the Dynamic Light Scattering (DLS) analysis supported the TEM results. PLAL technique is proved to be a simple method for producing carbon-based nanomaterials. Moreover, the laser ?uence was found to be an important factor which affects greatly the type of nanostructures that could be synthesized during laser ablation.
关键词： reduced graphene oxide,graphene,carbon-based nanomaterials,pulsed laser ablation
更新于2025-09-12 10:27:22
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Doping nanoparticles using pulsed laser ablation in a liquid containing the doping agent
摘要： While doping of semiconductors or oxides is crucial for numerous technological applications, its control remains difficult especially when the material is reduced down to the nanometric scale. In this paper, we show that pulsed laser ablation of an undoped solid target in an aqueous solution containing activator ions offers a new way to synthesise doped-nanoparticles. The doping efficiency is evaluated for laser ablation of an undoped Gd2O3 target in aqueous solutions of EuCl3 with molar concentration from 10?5 mol L?1 to 10?3 mol L?1. Thanks to luminescence experiments, we show that the europium ions penetrate the core of the synthesised monoclinic Gd2O3 nanoparticles. We also show that the concentration of the activators in the nanoparticles is proportional to the initial concentration of europium ions in the aqueous solution, and a doping of about 1% ([Eu]/[Gd] atomic ratio) is reached. On the one hand, this work could open new ways for the synthesis of doped nanomaterials. On the other hand, it also raises the question of undesired penetration of impurities in laser-generated nanoparticles in liquids.
关键词： EuCl3,doping,luminescence,pulsed laser ablation,Gd2O3,nanoparticles
更新于2025-09-11 14:15:04
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Sterilization for Bacillus Subtilis var. natto by Low Pressure Sputtering and Laser Ablation Plasma using Metal Powder Target
摘要： Effect of plasma sterilization for bacillus subtilis var. natto was studied using pulsed laser ablation and low pressure RF plasma, which usually used for functional thin film deposition. In addition, bulk and powder were used as the targets and compared the effect for the sterilization . Experimental results suggest that bacillus subtilis var. natto was not sterilized in the only vacuum state. However, they can be sterilized using low pressure RF plasma and pulsed laser ablation plasma irradiation. The effect of the sterilization using powder target was higher than that of bulk target, and that of the pulsed laser ablation plasma was higher than RF plasma. Those results suggest that the effect of sterilization was decided by the density of the high-energy metal atoms and ions.
关键词： plasma sterilization,plasma process,pulsed laser ablation
更新于2025-09-11 14:15:04
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Carbon coated TiO2 nanoparticles prepared by pulsed laser ablation in liquid, gaseous and supercritical CO2
摘要： We report on the synthesis of TiO2 nanoparticles using nanosecond pulse laser ablation of titanium in liquid, gaseous and supercritical CO2. The produced particles were observed to be mainly anatase-TiO2 with some rutile-TiO2. In addition, the particles were covered by a carbon layer. Raman and X-ray diffraction data suggested that the rutile content increases with CO2 pressure. The nanoparticle size decreased and size distribution became narrower with the increase in CO2 pressure and temperature, however the variation trend was different for CO2 pressure compared to temperature. Pulsed laser ablation in pressurized CO2 is demonstrated as a single step method for making anatase-TiO2/carbon nanoparticles throughout the pressure and temperature ranges 5–40 MPa and 30–50 °C, respectively.
关键词： core-shell particles,pulsed laser ablation,nanoparticle size control,supercritical fluids
更新于2025-09-11 14:15:04
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Producing graphene nanosheets by pulsed laser ablation: Effects of liquid environment
摘要： Effects of liquid environment on the characteristics of graphene nanosheets produced by the laser ablation method have been studied experimentally. The fundamental wavelength of a pulsed Nd:YAG laser at 1064 nm with 7 ns pulse width and 5 Hz repetition rate was employed to irradiate a graphite target in distilled water, liquid nitrogen, alcohol, acetone, and two concentrations of cetyltrimethylammonium bromide. Produced carbon nanostructures were diagnosed using Ultraviolet-Visible-Near Infrared and Fourier transform infrared spectroscopy, x-ray diffraction, Raman spectroscopy, transmission electron microscopy, and field emission scanning electron microscope images. Results show that different carbon nanostructures such as carbon nanoparticles and fluorine, as well as graphene nanosheets were formed in various liquid environments. The size and morphology of nanostructures strongly depends on the liquid environments and, among these liquids, water is the most capable one to produce graphene nanosheets.
关键词： Raman,carbon nanoparticles,graphene nanosheets,graphite,pulsed laser ablation
更新于2025-09-11 14:15:04