Optical Spectroscopic Investigation of Ar/CH₃OH and Ar/N₂/CH₃OH Atmospheric Pressure Plasma Jets

Abstract

Ar/CH3OH and Ar/N2/CH3OH plasma jets were generated at atmospheric pressure by dual-frequency excitations. Two different cases were studied with focus laid on the generation of CN radicals. In one case Ar gas passed through a bubbler with saturated methanol steam but without addition of N2 (Ar/CH3OH plasma). In the other case N2 passed through the bubbler with saturated methanol steam (Ar/N2/CH3OH plasma). The optical emission lines of CN radicals have been observed in these two cases of plasma discharges. The addition of N2 can significantly increase the optical emission intensity of CN bands.

OES diagnostic of radicals in 33 MHz radio-frequency Ar/C2H5OH atmospheric pressure plasma jet

“…Figure 5 illustrates the variation of C (247.8 nm)/C 2 (516.4 nm), CN (388.3 nm)/C 2 (516.4 nm) and CH (431.3 nm)/C 2 (516.4 nm) emission intensity ratios as a function of the ethanol content from 0 to 4600 ppm. These ratios are much lower than that in [42]. These three curves have the similar variation tendency, gradually decreasing with the ethanol content increase, which indicated that the higher ethanol content is inclined to create the C 2 radicals.…”

“…The electron energy decays as the ethanol content increases due to the electron impact processes to ethanol molecules and their fragments. In [42], we had studied the OES of the same carbonaceous radicals with the similar hydrocarbon (methanol, CH 3 OH) and obtained the similar results. However, the RF excitation frequency (33 MHz) in this paper is much higher than that in [42] (2 MHz).…”

“…In [42], we had studied the OES of the same carbonaceous radicals with the similar hydrocarbon (methanol, CH 3 OH) and obtained the similar results. However, the RF excitation frequency (33 MHz) in this paper is much higher than that in [42] (2 MHz). From this research and the [42], it seems that the driving frequencies in the range of 2−33 MHz have little influence on the carbonaceous radicals.…”

“…The emission of N 2 and O lines will not be observed when ethanol content is larger than 1500 ppm. The effect of the molecular gases mixed in noble gas plasma has also been observed when other molecular species are added [38,41,42]. The emission intensity of OH (308.9 nm) has a nonlinear relation with ethanol content, and the maximum value at about 1100 ppm.…”

The Organosilicon thin Film Deposited Using an Atmospheric Pressure Dual‐Frequency 50 kHz/33 MHz Frequency MicroPlasma Jet

“…The main argon flow is fed into the quartz syringe with a constant flow rate of 1 slm (standard liters per minute) in every experiment. The TEOS content carried into the discharge region is calculated using Antoine equation [5]. The micro-plasma jet is directed toward a substrate which fixed at 2 mm apart from the quartz syringe nozzle.…”