Spatiotemporal optical emission spectroscopy to estimate electron density and temperature of plasmas in solution

Abstract

In this article, we discuss the electron density and the temperature of plasmas in solution, which produce an attractive reaction field for processing. The measurement of the electron density and the estimation of the electron temperature of the plasma in NaCl solution were performed using spatiotemporally resolved optical emission spectroscopy. The electron densities were estimated to be of the order of from the Stark broadening of the Hβ line. The electron temperatures of the plasma were estimated to be in the range of 0.2–1.4 eV based on the electron-neutral bremsstrahlung. The estimated values were confirmed to be consistent with the experimental values of voltage and current density in the assumption of the Boltzmann equation.

Aqueous dispersion of hexagonal boron nitride via plasma processing in a hydroquinone solution

“…The plasma was generated in a hydroquinone solution containing h-BN particles by a bi-polar pulsed voltage. The solution contained 70 ml of distilled water, 2 g of h-BN particles with a 0.2 µm mean diameter (Sigma-Aldrich, Ltd) and 4 g of hydroquinone (Wako Pure Chemical Corporation), mixed with a suitable quantity of NaCl (Wako Pure Chemical Corporation) to adjust their electrical conductivity to 300 µS cm -1 for stable plasma generation [24]. The electrodes were two parallel tungsten rods with 1 mm of diameter and insulated with alumina tubes, except the 5 mm tip, which was separated by a 3 mm gap.…”

Microsecond Electrical Breakdown in Water: Advances Using Emission Analysis and Cavitation Bubble Theory

“…As noted previously, these works presented different experimental conditions as they are related to the nonsymmetric configuration. For the pin-to-pin experiment, we can report that Inoue et al used the global emission from the whole interelectrode gap focusing on the H β line to estimate the electron density [ 27 ].…”

Contribution of active species generated in plasma to CO2 methanation

“…OES is an effective method to estimate the density of the generated active species. [45][46][47][48][49][50][51][52][53] Figure 6 shows the optical emission spectrum in plasma measured by OES at 300 s after the start of the discharge. In the spectrum (Fig.…”