Porous silicon & titanium dioxide coatings prepared by atmospheric pressure plasma jet chemical vapour deposition technique-a novel coating technology for photovoltaic modules

Atmospheric Pressure Plasma Jet (APPJ) is an alternative for wet processes used to make anti reflection coatings and smooth substrate surface for the PV module. It is also an attractive technique because of it’s high growth rate, low power consumption, lower cost and absence of high cost vacuum systems. This work deals with the deposition of silicon oxide from hexamethyldisiloxane (HMDSO) thin films and titanium dioxide from tetraisopropyl ortho titanate using an atmospheric pressure plasma jet (APPJ) system in open air conditions. A sinusoidal high voltage with a frequency between 19-23 kHz at power up to 1000 W was applied between two tubular electrodes separated by a dielectric material. The jet, characterized by Tg ~ 600-800 K, was mostly laminar (Re ~ 1200) at the nozzle exit and became partially turbulent along the jet axis (Re ~ 3300). The spatially resolved emission spectra showed OH, N2, N2+ and CN molecular bands and O, H, N, Cu and Cr lines as well as the NO2 chemiluminescence continuum (450-800 nm). Thin films with good uniformity on the substrate were obtained at high deposition rate, between 800 -1000 nm.s-1, and AFM results revealed that coatings are relatively smooth (Ra ~ 2 nm). The FTIR and SEM analyses were better used to monitor the chemical composition and the morphology of the films in function of the different experimental conditions. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

Effect of Plasma Treatment on Corrosion Layers of Bronze

Plasma chemical process for conservation of metallic objects is a relatively new way of effective and fast treatment of corroded objects. Removal of corrosion products is based on plasma chemical reduction of corrosion layers by radio-frequency (RF) low pressure hydrogen plasma. Model corrosion layers on bronze were studied. SEM/EDX analyses on corroded and treated samples were performed

Study of Nitrogen Atom Recombination by Optical Emission Spectroscopy

The reaction kinetics in nitrogen flowing afterglow was studied by optical emission spectroscopy. The DC flowing post-discharge in pure nitrogen was created in a quartz tube at the total gas pressure of 1000 Pa. The optical emission spectra were measured along the flow tube. It was found that N atoms are the most important particles in the late nitrogen afterglow. In order to explain the decrease of N atom concentration, it was also necessary to include the surface recombination of N atoms to the model

Preface: Bioplasmas and plasmas with liquids

The Bioplasma and Plasmas with Liquids joint conference of the COST Actions TD1208 Electrical discharges with liquids for future applications and MP1101 Biomedical applications of atmospheric pressure plasma technology was held in Bertinoro (Italy) on September 13-16, 2015. The purpose of the Bioplasma and Plasmas with Liquids joint conference was to bring together researchers of different fields, and to establish an open forum for presentation and discussion of the latest advances in the fields of electrical discharges with liquids and plasma medicine, by bridging the scientific communities associated with the COST Actions TD1208 Electrical discharges with liquids for future applications and MP1101 Biomedical applications of atmospheric pressure plasma technology

Utilisation of the High Speed Camera for the Pin-hole Discharge Diagnostics

The high speed camera was utilised for plasma diagnostics of the DC pin-hole discharge in electrolyte solutions. Two discharge modes were determined. Plasma channels were observed either in the bubble or outside the bubble in the bulk solution, which confirms both thermal and electron theory of the discharge ignition in liquid. In the diaphragm discharge, plasma streamers were better visible on the cathode side of the dielectric barrier because they formed significantly longer channels

GC-MS and GC-FID Analysis of Products from Glow Discharge in N2 + CH4 Mixture

This work extends our previous investigation of nitrogen-methane atmospheric glow discharge for the simulation of chemical processes in prebiotic atmospheres. Also reactions on surfaces of solid state bodies can be important. So in presented experiments the electrodes with different shapes and different surface areas were used. Exhaust products of discharge in this gas mixture were analyzed by Gas Chromatography - Mass Spectrometry (GC-MS) and Gas Chromatography - Flame Ionization Detector (GC-FID). The major products identified in chromatograms were hydrogen cyanide and acetylene

The Influence of CO2 Admixtures on Process in Titan's Atmospheric Chemistry

The exploration of planetary atmosphere is being advanced by the exciting results of the Cassin-Huygens mission to Titan. The complex chemistry revealed in such atmospheres leading to the synthesis of bigger molecules is providing new insights into our understanding of how life on Earth developed. In our experiments Titan's atmosphere is simulated in a glow discharge formed from a mixture of N2:CH4:CO2 gas. Samples of the discharge gas were analysed by GC-MS and FTIR. The major products identified in spectra were: hydrogen cyanide, acetylene and acetonitrile. The same compounds were detected in the FTIR: hydrogen cyanide, acetylene and ammonia. Whilst many of these compounds have been predicted and/or observed in the Titan atmosphere, the present plasma experiments provide evidence of both the chemical complexity of Titan atmospheric processes and the mechanisms by which larger species grow prior to form the dust that should cover much of the Titan's surface

Atmospheric pressure glow discharge generated in nitrogen-methane gas mixture: PTR-MS analyzes of the exhaust gas

This paper reports the results of an extensive study of with the in situ mass spectrometry analysis of gaseous phase species produced by an atmospheric plasma glow discharge in N2-CH4 gas mixtures (with methane concentrations ranging from 1% to 4%). The products are studied using proton-transfer-reaction mass spectrometry (PTR-MS). HCN and CH3CN are identified as the main gaseous products. Hydrazine, methanimine, methyldiazene, ethylamine, cyclohexadiene, pyrazineacetylene, ethylene, propyne and propene are identified as minor compounds. All the detected compounds and their relative abundances are determined with respect to the experimental conditions (gas composition and applied power). The same molecules were observed by the Cassini-Huygens probe in Titan's atmosphere (which has same N2-CH4 gas mixtures). Such, experiments show that the formation of such complex organics in atmospheres containing C, N and H, like that of Titan, could be a source of prebiotic molecules

The influence of admixtures on the composition of products by nitrogen-methane atmospheric glow discharge

This work extends our experimentally studies with simulation of Titan's atmosphere by atmospheric glow discharge. This work is devoted to estimate the influence of CO2 and/or CO on reactivity in the Titan's atmosphere. The exploration of planetary atmosphere is being advanced by the exciting results of the Cassin-Huygens mission to Saturn and Titan, its most famous moon. Most of the studies were mainly interested in the reactivity of the N2-CH4 gaseous mixture and with the primary products of reactions, but the atmosphere of Titan also contains oxygenated volatile species

Organic chemistry of NH₃ and HCN induced by an atmospheric abnormal glow discharge in N₂-CH₄ mixtures

The formation of the chemical products produced in an atmospheric glow discharge fed by a N2-CH4 gas mixture has been studied using Fourier Transform InfraRed (FTIR) and Optical Emission Spectrometry (OES). The measurements were carried out in a flowing regime at ambient temperature and pressure with CH4 concentrations ranging from 0.5% to 2%. In the recorded emission spectra the lines of the second positive system CN system and the first negative system of N2 were found to be the most intensive but atomic Hα, Hβ, and C (247 nm) lines were also observed. FTIR-measurements revealed HCN and NH3 to be the major products of the plasma with traces of C2H2. These same molecules have been detected in Titan's atmosphere and the present experiments may provide some novel insights into the chemical and physical mechanisms prevalent in Titan's atmosphere with these smaller species believed to be the precursors of heavier organic species in Titan's atmosphere and on its surface