Nanoparticle formation by laser ablation in air and by spark discharges at atmospheric pressure

Itina, Tatiana E.; Voloshko, A.

doi:10.1007/s00340-013-5490-6

Cited by 33 publications

(21 citation statements)

References 46 publications

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“…To study femtosecond laser ablation, such approaches as molecular dynamics (MD), hydrodynamics (HD), and combinations with the direct simulation Monte Carlo method (DSMC) were proposed [44,45,46,47,48,49,50]. In particular, the MD-DSMC combination allows one to properly account for both the processes of cluster ejection and their following evolution during the laser plume expansion as a result of the gas-phase collisions.…”

Section: Introductionmentioning

confidence: 99%

Laser-based synthesis of nanoparticles: role of laser parameters and background conditions

2014

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International audienceLaser ablation (LA) is a unique tool for nanoparticle synthesis. The main advantages of this method are in its green character and in the possibility of a control over particle size. In this study, we examine nanoparticle formation by laser ablation under different experimental conditions and analyse the results based on the developed models. The dynamics of the laser plume expansion is examined revealing the role of the background pressure and laser pulse parameters. As a result, the ablated material is compressed and a part of it becomes supersaturated. The so-called "primary" nanoparticles are formed at this stage. Then, nanoparticle aggregation/fragmentation enters into play leading to the formation of the secondary particles. In addition, laser- assisted fragmentation of nanoparticles is also examined. Based on numerical modeling we shed light on the above mechanisms by using different numerical approaches, such as molecular dynamics, Monte Carlo, numerical hydrodynamics, and analytical analysis. Calculations are performed for metallic targets under different background conditions. The obtained results explain recent experimental findings and help to predict the role of the experimental parameters. The performed analysis thus indicates ways of a control over nanoparticle synthesis © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

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Section: Introductionmentioning

confidence: 99%

Laser-based synthesis of nanoparticles: role of laser parameters and background conditions

2014

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“…A promising production method is electric ablation in a spark discharge generator (SDG), which can generate nanoparticles of basically any non-insulating material that can be shaped into a set of electrodes (Meuller et al 2012) and is not limited to unary material systems (Kim and Chang 2005;Byeon et al 2008;Tabrizi et al 2009;Blomberg et al 2013;Muntean et al 2016;Kala et al 2016). In SDG, the particle purity is mainly limited by the electrode material and the carrier gas, and is even comparable to the particle purity for laser ablation (Itina andVoloshko 2013, Pfeiffer et al 2014). Furthermore, SDG has the potential to be up-scaled for industrial nanoparticle production by using, for example, several energy-efficient switched SDG units (Pfeiffer et al 2014) in parallel (Feng et al 2016a) at kHz discharge frequencies (Noh et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Hydrogen-assisted spark discharge generated metal nanoparticles to prevent oxide formation

Hallberg

Ludvigsson

Preger

et al. 2017

Aerosol Science and Technology

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There exists a demand for production of metal nanoparticles for today's emerging nanotechnology. Aerosol-generated metal nanoparticles can oxidize during particle formation due to impurities in the carrier gas. One method to produce unoxidized metal nanoparticles is to first generate metal oxides and then reduce them during sintering. Here, we propose to instead prevent oxidation by introducing the reducing agent already at particle formation. We show that by mixing 5% hydrogen into the nitrogen carrier gas, we can generate single crystalline metal nanoparticles by spark discharge from gold, cobalt, bismuth, and tin electrodes. The non-noble nanoparticles exhibit signs of surface oxidation likely formed post-deposition when exposed to air. Nanoparticles generated without hydrogen are found to be primarily polycrystalline and oxidized. To demonstrate the advantages of supplying the reducing agent at generation, we compare to nanoparticles that are generated in nitrogen and sintered in a hydrogen mixture. For bismuth and tin, the crystal quality of the particles after sintering is considerably higher when hydrogen is introduced at particle generation compared to at sintering, whereas for cobalt it is equally effective to only add hydrogen at sintering. We propose that hydrogen present at particle generation prevents the formation of oxide primary particles, thus improving the ability to sinter the nanoparticles to compact and single crystals of metal. This method is general and can be applied to other aerosol generation systems, to improve the generation of size-controlled nanoparticles of non-noble metals with a suitable reducing agent.

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“…Only a few detailed studies can be found in literature attempting to describe the NP generation process in spark discharges. 2,[8][9][10] In our view, one of the key reasons for this is that most of the studies being published on SDGs are conducted with an engineering application in mind. Another point is that the appealing simplicity of the technical realization of NP production is hiding away the very complex nature of the underlying physical and chemical processes.…”

Section: Introductionmentioning

confidence: 99%

A time-resolved imaging and electrical study on a high current atmospheric pressure spark discharge

Palomares

Kohut

Galbács

et al. 2015

Journal of Applied Physics

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A time-resolved laser induced fluorescence study on the ion velocity distribution function in a Hall thruster after a fast current disruption Phys. Plasmas 16, 043504 (2009) We present a time-resolved imaging and electrical study of an atmospheric pressure spark discharge. The conditions of the present study are those used for nanoparticle generation in spark discharge generator setups. The oscillatory bipolar spark discharge was generated between two identical Cu electrodes in different configurations (cylindrical flat-end or tipped-end geometries, electrode gap from 0.5 to 4 mm), in a controlled co-axial N 2 flow, and was supplied by a high voltage capacitor. Imaging data with nanosecond time resolution were collected using an intensified CCD camera. This data were used to study the time evolution of plasma morphology, total light emission intensity, and the rate of plasma expansion. High voltage and high current probes were employed to collect electrical data about the discharge. The electrical data recorded allowed, among others, the calculation of the equivalent resistance and inductance of the circuit, estimations for the energy dissipated in the spark gap. By combining imaging and electrical data, observations could be made about the correlation of the evolution of total emitted light and the dissipated power. It was also observed that the distribution of light emission of the plasma in the spark gap is uneven, as it exhibits a "hot spot" with an oscillating position in the axial direction, in correlation with the high voltage waveform. The initial expansion rate of the cylindrical plasma front was found to be supersonic; thus, the discharge releases a strong shockwave. Finally, the results on equivalent resistance and channel expansion are comparable to those of unipolar arcs. This shows the spark discharge has a similar behavior to the arc regime during the conductive phase and until the current oscillations stop. V C 2015 AIP Publishing LLC. [http://dx

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Nanoparticle formation by laser ablation in air and by spark discharges at atmospheric pressure

Cited by 33 publications

References 46 publications

Laser-based synthesis of nanoparticles: role of laser parameters and background conditions

Laser-based synthesis of nanoparticles: role of laser parameters and background conditions

Hydrogen-assisted spark discharge generated metal nanoparticles to prevent oxide formation

A time-resolved imaging and electrical study on a high current atmospheric pressure spark discharge

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