Submicron particle chemistry: Vapor condensation analogous to liquid solidification

Jenkins, N; Eagar, T. W.

doi:10.1007/s11837-003-0138-3

Cited by 12 publications

(7 citation statements)

References 6 publications

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“…The rate of temperature decrease, the so-called quenching rate, was estimated to be (5.5±0.6)×10 8 Ks -1 . This value fits into the 10 6 -10 9 Ks -1 range reported in the literature (Feng et al 2016, Berkowitz and Walter 1987, Jenkins and Eagar 2003, Martinen and Toll 1970, although it is closer to the higher end of the literature range. Recently Feng et al estimated the quenching rate in an SDG for gold vapour in nitrogen atmosphere and obtained 7.5×10 6 Ks -1 (Feng et al 2016), which is almost two orders of magnitude smaller than the value we report here.…”

Section: Quenching Rate and Particle Formationsupporting

confidence: 87%

From plasma to nanoparticles: optical and particle emission of a spark discharge generator

et al. 2017

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The increased demand for high purity nanoparticles (NPs) of defined geometry necessitates the continuous development of generation routes. One of the most promising physical techniques for producing metal, semiconductor or alloy NPs in the gas phase is spark discharge NP generation. The technique has a great potential for up-scaling without altering the particles. Despite the simplicity of the setup, the formation of NPs in a spark discharge takes place via complex multi-scale processes, which greatly hinders the investigation via conventional NP measurement techniques. In the present work, time-resolved optical emission spectroscopy (OES) was used to provide information on the species present in the spark from as early as approximately 100 ns after the initiation of the discharge. We demonstrate that operando emission spectroscopy can deliver valuable insights into NP formation. The emission spectra of the spark are used to identify, among others, the main stages of material erosion and to calculate the quenching rate of the generated metal vapour. We demonstrate that the alteration of key control parameters, that are typically used to optimize NP generation, clearly affect the emission spectra. We report for Cu and Au NPs that the intensity of spectral lines emitted by metal atoms levels off when spark energy is increased above an energy threshold, suggesting that the maximum concentration of metal vapour produced in the generator is limited. This explains the size variation of the generated NPs. We report a strong correlation between the optical and particle emission of the spark discharge generator, which demonstrate the suitability of OES as a valuable characterization tool that will allow for the more deliberate optimization of spark-based NP generation.

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Section: Quenching Rate and Particle Formationsupporting

confidence: 87%

From plasma to nanoparticles: optical and particle emission of a spark discharge generator

et al. 2017

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“…[13][14][15] The micrograph thus justifies the assumption 1) that the cooling time from the boiling point to the carrier gas temperature T c (usually room temperature) is so short that the reported that multiple domains will be formed if the NPs coalesce at room temperature. 16 Sparks or laser ablation configurations with a higher energy per pulse or a higher repetition frequency than the one we used would still fulfill this condition of "rapid quenching" when the gas flow rate is increased accordingly.…”

Section: Section S6 Proximity Collection Of the Early Stage Clustersmentioning

confidence: 62%

“…A vapor cloud is drastically quenched while being carried away by the gas flow. The instantaneous quenching of the vapor cloud from boiling temperature to T c (i.e., ranging from 10 6 to 10 9 K s –1 ) − causes an infinitely large supersaturation (cf., Supporting Information section S1). As a result, the extremely high supersaturation pushes the critical nucleus size to the atomic range which subsequently grow to NPs by particle–particle collisions and sticking; a process commonly referred to as coagulation .…”

Section: Theoretical Frameworkmentioning

confidence: 99%

General Approach to the Evolution of Singlet Nanoparticles from a Rapidly Quenched Point Source

et al. 2015

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Among the numerous point vapor sources, microsecond-pulsed spark ablation at atmospheric pressure is a versatile and environmentally friendly method for producing ultrapure inorganic nanoparticles ranging from singlets having sizes smaller than 1 nm to larger agglomerated structures. Due to its fast quenching and extremely high supersaturation, coagulational growth already begins at the atomic scale at room temperature. On the basis of this knowledge, we develop a simple semiempirical yet versatile model for predicting the size distribution of singlet particles as a function of the process conditions. The model assumes that a plume of a turbulent aerosol flow flares out from a concentrated point source, eventually reaching the walls of the confinement where a fraction of the particles is deposited. Despite the complexity of the entire process, the concentration and size evolution of particles can be adequately described by a first-order differential equation accounting for coagulation, turbulent dilution, and diffusional deposition to the walls. The model provides a simple and practical tool that can generally be used to design and control point vapor source reactors for the synthesis of singlets with tunable sizes starting from that of single atoms.

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“…in the arc stage, is in the range of 15000-20000 K (see temporally resolved emission spectra acquired in a nitrogen atmosphere. This value fits into the 6 -10 9 Ks -1 range declared in the literature [77,86,164,165], and it is closer to the higher end of the reported range. Recently Feng et al estimated the quenching rate in an SDG for gold vapor in nitrogen atmosphere and obtained 7.5×10 6 Ks -1 [77], which is almost two orders of magnitude smaller than the value I obtained.…”

Section: Particle Formationsupporting

confidence: 89%

On the plasma and electrode erosion processes in spark discharge nanoparticle generators

Kohut¹

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Submicron particle chemistry: Vapor condensation analogous to liquid solidification

Cited by 12 publications

References 6 publications

From plasma to nanoparticles: optical and particle emission of a spark discharge generator

From plasma to nanoparticles: optical and particle emission of a spark discharge generator

General Approach to the Evolution of Singlet Nanoparticles from a Rapidly Quenched Point Source

On the plasma and electrode erosion processes in spark discharge nanoparticle generators

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