Microscopic Optical Discharge Cell for Micro-Spectroscopic Measurements of Plasma in Solutions and Its Chemical-contrasted Imaging

Yui, Hiroharu; Someya, Yuu; Kusama, Yuta; Kanno, Kenta; Takakuwa, H.

doi:10.2116/bunsekikagaku.62.19

Cited by 7 publications

(22 citation statements)

References 7 publications

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“…Our previous observation has clarified that the ASG plasma is formed in a bubble generated in the solution. 15) The continuum emission may result from the heated bubble, similar to that shown in Ref. 29.…”

Section: Time-resolved Emission Spectra From the Asg Plasmasupporting

confidence: 66%

“…1) From the microscopic image, the ASG plasma spatially fills almost the entire part of the gap between the electrodes. 15) Although the ASG plasma can be classified as a glow plasma from its spatial distribution, the differences among T b , T H , and T OH are, interestingly, not large, differently from the ordinal glow plasma generated under low pressure. The high temperature of the radicals should result from the high collision frequency of the particles since the plasma is formed under atmospheric pressure.…”

Section: Time-resolved Emission Spectra From the Asg Plasmamentioning

confidence: 99%

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Nanosecond time-resolved microscopic spectroscopy for diagnostics of an atmospheric-pressure discharge plasma formed in aqueous solution

Banno

Kanno

Someya

et al. 2015

Jpn. J. Appl. Phys.

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Glow discharge plasma formed in solution under atmospheric pressure has been expected to provide reaction fields with characteristic physical and chemical properties owing to the frequent collisions and reactions of reactive particles inside and the rapid quenching of the products by the surrounding cold solutions. In particular, when an aqueous solution is utilized as the surrounding solution, the atmospheric-pressure in-solution glow (ASG) plasma contains hydrogen and hydroxyl radicals showing large activities for reduction and oxidation, respectively. In addition, because the ASG plasma is formed under atmospheric pressure, the collision frequencies between the particles contained in the plasma are higher than those in other plasmas ordinarily formed under low pressure. This feature should result in rapid energy redistribution among particles contained in the plasma. In the present study, time-resolved optical emission spectroscopy with nanosecond time resolution was applied for the diagnostics of the ASG plasma with chemical species selectivity. The time-resolved measurements revealed that the temporal evolutions of the temperatures of blackbody, hydrogen radical, and hydroxyl radical contained in the ASG plasma consist of two stages: initial rise within 0.15 µs (rising stage) and fluctuation around certain values for about 1 µs (fluctuating stage). In the time region corresponding to the rising stage, the electron number density is about ten times larger than the value temporally averaged during the plasma emission. The initial rise should result from frequent collisions between charged particles accelerated by the applied voltage and unexcited particles. In the fluctuating stage, the electron number density strongly correlates with the increase in the radical temperatures. It is concluded that the electron number density, rather than the electron temperature, is a key parameter determining the temperatures of reactive species in the ASG plasma.

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Section: Time-resolved Emission Spectra From the Asg Plasmasupporting

confidence: 66%

Section: Time-resolved Emission Spectra From the Asg Plasmamentioning

confidence: 99%

Nanosecond time-resolved microscopic spectroscopy for diagnostics of an atmospheric-pressure discharge plasma formed in aqueous solution

Banno

Kanno

Someya

et al. 2015

Jpn. J. Appl. Phys.

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“…The detailed information on the system is described elsewhere. 3,5 The m-ASS plasmas were generated in a gap between two opposed tungsten electrodes with the diameters of 0.25 mm. The electrodes were confined in the cell.…”

Section: Methodsmentioning

confidence: 99%

“…4,5 Since the plasma spatially fills almost the whole part of the gap like glow discharge, we denote it as atmosphericpressure in-solution glow (ASG) plasma. We have studied and analyzed the emission spectrum from the ASG plasma with the time resolution of nanoseconds.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve this condition, we developed and applied a nanosecond OES system based on a custom-made discharge cell and a microscope. 5 With the microscopic spectrometer, we succeeded in obtaining the emission spectra from the +plasma and the -plasma separately. We identified the components contained in the plasmas and quantitatively estimated the temperatures of them from the emission spectra analyses.…”

Section: Introductionmentioning

confidence: 99%

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Time-and Space-resolved Optical Diagnostics for Discharge Plasmas Separately Formed in Aqueous Solution

2017

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Development of direct gas injection system for atmospheric-pressure in-solution discharge plasma for plasma degradation and material syntheses

2016

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By applying a high pulsed voltage to a gap between two electrodes placed in a solution, an atmosphericpressure in-solution glow (ASG) plasma is generated. The ASG plasma is applied in a new material processing method, called solution plasma processing (SPP). In order to accelerate the reaction and to add functions to the synthesized materials, it is important to alter the gas content in the ASG plasma. We developed a direct gas injection system for an ASG discharge cell. When O 2 , CO 2 , N 2 and Ar gases were injected into the ASG plasma, emission bands due to the derivatives of the injected gases were observed in the emission spectra from the ASG plasma. The electron number density in the ASG plasma was increased by the O 2 , CO 2 , and N 2 injections, probably due to the enhancements of the a and g processes by the larger molecular weights than H 2 O. In addition, the first dielectric breakdown of the solution and the formation of the gas bubble processes gradually disappeared due to the gas injection.When O 2 was injected, the amount of $OH generation was increased. By the enhancement of the $OH generation, the degradation speed of rhodamine B in the ASG plasma was increased by a factor of two. When Au nanoparticles were synthesized utilizing the ASG plasma, the zeta potential of the Au nanoparticles was increased by about 30% by the O 2 injection. The plasma parameters and the reactivity of the ASG plasma can be altered more widely by changing the kind of injected gas and the flow rate.

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Microscopic Optical Discharge Cell for Micro-Spectroscopic Measurements of Plasma in Solutions and Its Chemical-contrasted Imaging

Cited by 7 publications

References 7 publications

Nanosecond time-resolved microscopic spectroscopy for diagnostics of an atmospheric-pressure discharge plasma formed in aqueous solution

Nanosecond time-resolved microscopic spectroscopy for diagnostics of an atmospheric-pressure discharge plasma formed in aqueous solution

Time-and Space-resolved Optical Diagnostics for Discharge Plasmas Separately Formed in Aqueous Solution

Development of direct gas injection system for atmospheric-pressure in-solution discharge plasma for plasma degradation and material syntheses

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