• Carbon letters
• /
• v.4 no.2
• /
• pp.74-78
• /
• 2003

Four kinds of plasma blacks were prepared by plasma pyrolysis under various metallic catalysts coated on honeycomb, and investigated the catalytic effect on the characteristics of the plasma blacks prepared under plasma pyrolysis condition. Pt, Pt-Rh, and Pd catalysts were employed as active materials to prepare the plasma blacks. In the experimental range studied, the metallic catalysts influenced on surface area, particle size, surface oxygen content and electrical conductivity of the plasma blacks prepared. It was showed that more dense particle of plasma blacks were prepared under existence of metallic catalysts. Presence of the metallic catalyst reduces the electrical resistivity of plasma blacks due to the decrease in the amount of oxygen functional groups. The highest electrical conductivity of plasma black was observed in the Pt catalyst and then followed by those Pt-Rh, Pd and bare cordierite honeycomb.

• Journal of Powder Materials
• /
• v.19 no.5
• /
• pp.343-347
• /
• 2012

In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nanoparticles. The effect of the debinding methods on the phase, microstructure and electrical conductivity of the screen-printed patterns was systematically investigated by FE-SEM, TGA, XRD and four-point probe analysis. The patterns formed using oxygen plasma debinding showed the well-developed microstructure and the superior electrical conductivity compared with those of using thermal debinding.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.80-83
• /
• 2005

In this work, effects of oxygen plasma on surface characteristics of carbon fibers were investigated in mechanical properties interfacial of carbon fibers-reinforced composites. The surface properties of the carbon fibers were determined by acid/base values, FT-IR, and X-ray photoelectron spectroscopy (XPS). Also, the mechanical properties of the composites were studied in and critical stress intensity factor ($K_{IC}$) and critical strain energy release rate mode II ($G_{IIC}$) measurements. As experimental results, the $O_{lS}/C_{lS}$ ratio of the carbon fiber surfaces treated by oxygen plasma was increased compared to that of untreated ones, possibly due to development of oxygen-containing functional groups. The mechanical properties of the composites, including $K_{IC}$ and $G_{IIC}$ had been improved in the oxygen plasma on fibers. These results could be explained that the oxygen plasma was resulted in the increase of the adhesion of between fibers and matrix in a composite system.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.198.2-198.2
• /
• 2016

Reactive oxygen and nitrogen species (RONS) can be generated by using non-thermal atmospheric pressure plasma jet which have profound biomedical applications [1, 2]. In this work, reactive oxygen species like hydroxyl radical (OH) are generated by using non-thermal direct plasma jet above water surface using Ar gas and their properties have been studied using ultraviolet absorption spectroscopy. OH radicals are found to be generated simultaneously with the discharge current with concentration of $2.7{\times}1015/cm3$ at 7mm above water surface while their persistence time have been measured to be $2.8{\mu}S$. In addition, it has been shown that plasma initiated ultraviolets play a major role to generate RONS inside water. Further works are going on to measure the temporal behavior of OH and $O2^*-$.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.6
• /
• pp.261-266
• /
• 2003

We investigated the effect of oxygen plasma treatment of indium-tin oxide(ITO) surface on the performance of electroluminescence(EL) devices. ITO surface treated oxygen plasma has been analyzed using atomic force microscope(AFM) and X-ray photoelectron spectroscopy(XPS), to investigate the relations between the properties of the ITO surface and the properties of the current-voltage-luminance(I-V-L) characteristics of the fabricated OLED with the structure of ITO(plasma treatment) / TPD / Alq$_3$/ Al. It is found that the oxygen plasma treatment of ITO anode improve the hole injection of the OLED due to the modification of the surface states. The treated ITO anode nay be low voltage with high luminance efficiency.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.6
• /
• pp.577-585
• /
• 2014

A series of experiments using atmospheric-pressure non-thermal plasma coupled with transition metal catalysts were performed to remove ethylene from agricultural storage facilities. The non-thermal plasma was created by dielectric barrier discharge, which was in direct contact with the catalyst pellets. The transition metals such as Ag and $V_2O_5$ were supported on ${\gamma}-Al_2O_3$. The effect of catalyst type, specific input energy (SIE) and oxygen content on the removal of ethylene was examined to understand the behavior of the hybrid plasma-catalytic reactor system. With the other parameters kept constant, the plasma-catalytic activity for the removal of ethylene was in order of $V_2O_5/{\gamma}-Al_2O_3$ > $Ag/{\gamma}-Al_2O_3$ > ${\gamma}-Al_2O_3$ from high to low. Interestingly, the rate of plasma-catalytic ozone generation was in order of $V_2O_5/{\gamma}-Al_2O_3$ > ${\gamma}-Al_2O_3$ > $Ag/{\gamma}-Al_2O_3$, implying that the catalyst activation mechanisms by plasma are different for different catalysts. The results obtained by varying the oxygen content indicated that nitrogen-derived reactive species dominated the removal of ethylene under oxygen-lean condition, while ozone and oxygen atoms were mainly involved in the removal under oxygen-rich condition. When the plasma was coupled with $V_2O_5/{\gamma}-Al_2O_3$, nearly complete removal of ethylene was achieved at oxygen contents higher than 5% by volume (inlet ethylene: 250 ppm; gas flow rate: $1.0Lmin^{-1}$; SIE: ${\sim}355JL^{-1}$).

• Applied Chemistry for Engineering
• /
• v.33 no.1
• /
• pp.38-43
• /
• 2022

The effect of introducing oxygen functional groups by oxygen plasma treatment of activated carbon on adsorption properties of cesium ions was investigated. During the oxygen plasma treatment, the frequency, power, and oxygen gas flow rates were fixed at 100 kHz, 80 W, and 60 sccm, respectively, while the reaction time was varied. Under the experimental conditions, the amount of cesium ion adsorption increased as the content of oxygen groups on C-O-C and O=C-O bonds increased when the reaction time with oxygen gas was 10 minutes. However, when the reaction time increased to 15 minutes, the oxygen functional group content decreased resulting in the decrease of the adsorbed cesium ion amount. On the other hand, unlike the oxygen content of the surface-treated activated carbon, the specific surface area and pore properties were hardly affected by the oxygen plasma reaction time. As a result, the oxygen plasma-treated activated carbon improved the cesium ion removal rate by up to 97.3% compared to that of the untreated activated carbon. This is considered to be due to the content of oxygen groups on C-O-C and O=C-O bonds introduced on the surface of the activated carbon through oxygen plasma treatment.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.118-120
• /
• 2009

We reported that the evidence of oxygen doping to copper-phthalocyanine (CuPc) by $O_2$-plasma treatment to Au electrode of inverted top emitting organic light emitting diodes (ITOLEDs). The operation voltage of OLEDs at 150 mA/$cm^2$ decreased from 16.1 to 10.3 V as oxygen atoms indiffued to CuPc layer using $O_2$-plasma. Synchrotron radiation photoelectron spectroscopy results showed that a new bond of Cu-O appeared and the energy difference between the highest occupied molecular orbital and $E_F$ is lowered by 0.20 eV after plasma treatment. Thus the hole injection barrier was lowered, reducing the turn-on voltage and increasing the quantum efficiency of OLEDs.

• Journal of Microbiology
• /
• v.44 no.4
• /
• pp.466-471
• /
• 2006

In this study, we attempted to characterize the biomolecular effects of an atmospheric-pressure cold plasma (APCP) system which utilizes helium/oxygen $(He/O_2)$. APCP using $He/O_2$ generates a low level of UV while generating reactive oxygen radicals which probably serve as the primary factor in sterilization; these reactive oxygen radicals have the advantage of being capable to access the interiors of the structures of microbial cells. The damaging effects of plasma exposure on polypeptides, DNA, and enzyme proteins in the cell were assessed using biochemical methods.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.2
• /
• pp.113-117
• /
• 2016

Temperature dependent reverse-bias current-voltage (I-V) characteristics in Cu Schottky contacts to oxygen plasma treated n-InP were investigated. For untreated sample, current transport mechanisms at low and high temperatures were explained by thermionic emission (TE) and TE combined with barrier lowering, respectively. For plasma treated sample, experimental I-V data were explained by TE or TE combined with barrier lowering models at low and high temperatures. However, the current transport was explained by a thermionic field emission (TFE) model at intermediate temperatures. From X-ray photoemission spectroscopy (XPS) measurements, phosphorus vacancies (VP) were suggested to be generated after oxygen plasma treatment. V_P possibly involves defects contributing to the current transport at intermediate temperatures. Therefore, minimizing the generation of these defects after oxygen plasma treatment is required to reduce the reverse-bias leakage current.