Surface characteristics of indium tin oxide deposited by facing target sputtering and its effect on the performance of organic light emitting diode

Chul Yoon,Sang-Ho Kim 한국물리학회 2009 Current Applied Physics Vol.9 No.3

A new facing target sputtering (FTS) method that has two facing targets and substrate locates vertically to the targets was used for ITO anode deposition in OLED. The ITO different from it by a conventional DC or RF magnetron sputtering was optimized in crystallinity, grain morphology, surface roughness and oxygen content by plasma treatment, and the effect on the OLED I–V characteristic was identified. Crystallinity of ITO was improved with a short plasma treatment time less than 15 min. The grains were an equi-axed as deposited state and changed to columnar grains when the plasma treatment time was exceeded above 20 min. The surface roughness was maintained within the targeted 1.8–2.0 nm range with plasma treatment from 5 to 20 min. Oxygen content measured using XPS analysis was increased with 15 min plasma treatment during the ITO grains maintained an equi-axed, but it was decreased again with 25 min plasma treatment. The I–V characteristic of OLED was relatively good with 15 min plasma treatment. It was considered because the ITO anode can contain higher oxygen in equi-axed grains, and can have better crystallinity and relevant surface roughness by 15 min plasma treatment. A new facing target sputtering (FTS) method that has two facing targets and substrate locates vertically to the targets was used for ITO anode deposition in OLED. The ITO different from it by a conventional DC or RF magnetron sputtering was optimized in crystallinity, grain morphology, surface roughness and oxygen content by plasma treatment, and the effect on the OLED I–V characteristic was identified. Crystallinity of ITO was improved with a short plasma treatment time less than 15 min. The grains were an equi-axed as deposited state and changed to columnar grains when the plasma treatment time was exceeded above 20 min. The surface roughness was maintained within the targeted 1.8–2.0 nm range with plasma treatment from 5 to 20 min. Oxygen content measured using XPS analysis was increased with 15 min plasma treatment during the ITO grains maintained an equi-axed, but it was decreased again with 25 min plasma treatment. The I–V characteristic of OLED was relatively good with 15 min plasma treatment. It was considered because the ITO anode can contain higher oxygen in equi-axed grains, and can have better crystallinity and relevant surface roughness by 15 min plasma treatment.

정신분열증환자의 혈장 Homovanillic Acid 농도와 치료반응과의 관계

조주연,기백석,박두병 大韓神經精神醫學會 1996 신경정신의학 Vol.35 No.3

In order to see whether the plasma homovanillic acid(HVA) levels can be adopted as a predictive biological marker reflecting therapeutic response of haloperidol, the authors measured HVA levels in 10 shchizophrenic patient and analyzed their relationship to therapeutic response. The measurement of plasma HVA level were carried out with high performance liquid chromatography(HPLC) before and after 7, 28days of treatment and the therapeutic response were assessed with Brief Psychiatric Rating Scale(BPRS) before and after 28days of treatment. The results of this study were as follows. 1) Plasma HVA levels after 7 days of treatment were significantly increased as compared to baseline plasma HVA levels and plasma HVA levels after 28 days of treatment were significantly decreased compared to levels after 7 days of treatment. 2) Significant correlation was found between baseline plasma HVA levels and clinical improvement after 28 days of treatment. 3) There was significant correlation between increase in plasma HVA level after 7 days and clinical improvement after 28 days of treatment. But there was no significant correlations between decrement in plasma HVA level from 7 days to 28 days and clinical improvement after 28 days of treatment. Hence theses observations have led us to propose that the early changes in plasma HVA levels are predictive of eventual treatment response.

Photocatalytic effects of plasma-heated TiO2−x particles under visible light irradiation

YoonKeun Chae,박진원,Shinsuke Mori,Masaaki Suzuki 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.1

The photocatalytic characteristics of partially reduced TiO2 (TiO2−x) by plasma treatment and plasma-heated treatment were investigated in the visible-light region. For the visible-light photocatalytic activity of TiO2−x, plasmaheated treatment shows stronger than plasma treatment significantly. The TiO2−x by plasma-heated treatment shows broader red-shifted absorption bands than one by plasma treatment in the visible-light region. The surface color of TiO2−x by plasma treatment and plasma-heated treatment changed from white to sky blue, and to navy, respectively. After exposure to air, the surface color of TiO2−x changed from sky blue to white for plasma treatment and from navy to beige for plasma-heated treatment.

부탄올 분리용 투과증발 복합막 제조

김성수,김현영 한국막학회 2009 멤브레인 Vol.19 No.1

부탄올을 투과증발 공정으로 분리하기 위하여 복합공정에 의하여 투과증발막을 제조하였다. 상업용 poly(dime-thylsiloxane) (PDMS) 막을 plasma 처리시키거나, polysulfone, poly(ether imide) 막을 지지체로 사용하여 plasma 처리 및 PDMS 코팅의 복합공정을 적용하였다. 헥산계열과 실란계열 유기 화합물을 사용하여 PDMS막을 plasma 처리하였을 경우 막 표면의 소수성을 증가시켜서 부탄을 선택도가 12.56까지 향상되었다. 반면에 투과량은 막 표면의 소수성 증대와 free volume의 변화로 인해 1.15 kg/m 2 ·hr까지 감소되어 선택도와 반대의 성향을 나타내었다. 막의 소수성이 증가함에 따라 접촉각과 상대적 sorption 비가 증가하였고, 부탄을 선택도도 향상되었다. PDMS 코팅 용액에서 prepolymer의 함량이 높을수록 부탄올 선택도가 증가하였다. PDMS 코팅과 plasma 처리 공정의 순서에 따른 영향을 조사하였다. 부탄올과 노르말 헥산으로 plasma 처리할 경우 plasma처리, PDMS 코팅 순으로 제조된 막의 분리 성능이 우수하였고 hexamethyldisilane과 hex-amethyldisilazane을 사용한 경우에는 역순으로 제조된 막의 분리 성능이 더 우수한 것으로 나타났다. Pervaporation membrane for butanol separation was prepared by hybrid process. Plasma treatment of commercial poly(dimethylsiloxane) (PDMS) membrane was attempted and combination of plasma treatment and PDMS solution coating on polysulfone, poly(ether imide) supports were also performed. Plasma treatment of PDMS membrane with hexane and silane group compounds was performed to increase the hydrophobicity of the surface, which enhanced the separation factor upto 12.5 at the expense of flux decrease down to 1.15 kg/m 2 ·hr. Contact angle and relative sorption ratio were also related with hydrophobicity of the memrbane. Increase of PDMS prepolymer composition resulted in dense structure of coating layer with better separation factor. Effects of sequence of PDMS coating vs. plasma treatment were examined. It was found that plasma treatment with butanol and n-hexane plasma followed by PDMS coating showed better performance and vice versa for plasma treatment with hexamethyldisilane and hexamethyldisilazane.

Combined effects of direct plasma exposure and pre-plasma functionalized metal-doped graphene oxide nanoparticles on wastewater dye degradation

K. Navaneetha Pandiyaraj,D. Vasu,A. Raji,Rouba Ghobeira,Parinaz Saadat Esbah Tabaei,Nathalie De Geyter,Rino Morent,M.C. Ramkumar,M. Pichumani,R.R. Deshmukh 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

The current study investigates the combinatorial effect of the photocatalytic performance of plasma pretreatedTi-Cu-Zn doped graphene oxide (TCZ-GO) nanoparticles (NPs) and advanced oxidation processesof a non-thermal atmospheric pressure plasma on the degradation of reactive orange-122 (RO-122) dyecompounds. Firstly, in order to enhance the photocatalytic performance of the synthesized compositeNPs, they were subjected to glow discharge plasma treatments operating in different gases (Ar, air, O2and N2). Their surface morphology, chemical composition and band gap were examined by means ofscanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–Vis spectrophotometryrespectively. XPS results revealed that plasma-treated NPs exhibited a higher content of oxygenvacancies and a variation in their oxidation states (Ti4+?Ti3+, Cu+?Cu2+). These plasma-induced surfacechemical changes hindered the recombination of photo-generated electron-hole pairs which led to a dropin the bandgap of the NPs with N2 plasma-treated NPs acquiring the lowest bandgap. Lastly, the articleexamined the actual decomposition of RO-122 dye in wastewater by an Ar plasma treatment alone orcombined with the plasma-treated TCZ-GO NPs via spectrophotometric analyses, electrical conductivity,pH and total organic carbon (TOC) removal measurements. Moreover, the reactive species produced duringthe combined plasma/photocatalysis induced degradation were detected in situ by optical emissionspectroscopy. Results revealed that the processes carried out by combining N2 plasma-treated TCZ-GONPs and Ar plasma exhibited the highest degradation efficiency (85 %) due to the generation of moreOH and H2O2. Overall, it can be concluded that plasma-aided treatment processes used synergisticallyas indirect surface functionalization of TCZ-GO NPs and direct plasma treatment of wastewater are extremelyefficient in the degradation of toxic compounds and can be extrapolated to various environmentalapplications.

Control of Optical Properties by the Stepwise Chemical and Plasma Spray Treatment of Polycarbonate

전법주 한국진공학회 2018 Applied Science and Convergence Technology Vol.27 No.6

Using the Polycarbonate (PC) polymer sheet, the change in optical properties was compared by changing the surface shape with the primary chemical surface treatment and plasma spray treatment. Plasma treatment affects surface composition changes and has a small effect on surface structure changes. Changes in surface structure are important to control the optical characteristics of the PC polymer sheet. Thus, it was possible to control changes in surface composition and changes in surface structure through secondary plasma treatment after primary chemical treatment. The primary chemical treatment had a small effect on changes in the chemical composition of the surface, but the surface roughness was influenced by swelling. The secondary plasma spray treatment affected optical properties changes, which allowed control of changes in surface structure after primary chemical treatment. At the same time after the first chemical treatment, the secondary plasma treatment was easy to control of optical properties by changing the surface structure as well as the surface properties due to changes in chemical composition by surface cross-linking reaction.

Nanostructured PVDF membrane for MD application by an O₂ and CF₄ plasma treatment

Jeong, Seongpil,Shin, Bongsu,Jo, Wonjin,Kim, Ho-Young,Moon, Myoung-Woon,Lee, Seockheon Elsevier 2016 Desalination Vol.399 No.-

<P><B>Abstract</B></P> <P>Recently, various nanotechnologies have been utilized with regard to membrane modification due to their high activities and the low cost of the nanomaterials involved. In order to enhance the hydrophobicity of the membrane surface for membrane distillation applications by decreasing the surface energy, a radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) process is suggested with surface nanostructuring and a subsequent hydrophobic coating step. In this research, a commercial PVDF membrane was modified by plasma treatments with the two different gases of O<SUB>2</SUB> and CF<SUB>4</SUB>. The water contact angles of the active layers increased from 73 to 117 and 101° and the fluxes of the treated membranes increased to 63 and 27.9% as compared to a virgin PVDF membrane when the feed used was D.I. water by the O<SUB>2</SUB> and CF<SUB>4</SUB> plasma modifications, respectively. Defluorination at the long exposure time (120min) of the plasma treatment and increase of the overall hydrophobicity (the decrease of the contact angle hysteresis) by the HMDSO coating were the reasons of the flux variations for the plasma modified membranes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The PVDF membranes were modified by plasma treatments with O<SUB>2</SUB> and CF<SUB>4</SUB> gases. </LI> <LI> The modified membrane have an enhanced flux and hydrophobicity after the plasma treatment. </LI> <LI> The pore-size and porosity at the membrane surface increased after the plasma treatment. </LI> <LI> The hairy structure was formed at the membrane surface by the HMDSO coating. </LI> <LI> The O<SUB>2</SUB> plasma treatment with HMDSO coating increased the receding contact angle. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Control of Optical Properties by the Stepwise Chemical and Plasma Spray Treatment of Polycarbonate

Bup Ju Jeon 한국진공학회(ASCT) 2018 Applied Science and Convergence Technology Vol.27 No.6

Using the Polycarbonate (PC) polymer sheet, the change in optical properties was compared by changing the surface shape with the primary chemical surface treatment and plasma spray treatment. Plasma treatment affects surface composition changes and has a small effect on surface structure changes. Changes in surface structure are important to control the optical characteristics of the PC polymer sheet. Thus, it was possible to control changes in surface composition and changes in surface structure through secondary plasma treatment after primary chemical treatment. The primary chemical treatment had a small effect on changes in the chemical composition of the surface, but the surface roughness was influenced by swelling. The secondary plasma spray treatment affected optical properties changes, which allowed control of changes in surface structure after primary chemical treatment. At the same time after the first chemical treatment, the secondary plasma treatment was easy to control of optical properties by changing the surface structure as well as the surface properties due to changes in chemical composition by surface cross-linking reaction.

Fermi-level depinning in metal/Ge interface using oxygen plasma treatment

Janardhanam, Vallivedu,Yun, Hyung-Joong,Jyothi, Inapagundla,Yuk, Shim-Hoon,Lee, Sung-Nam,Won, Jonghan,Choi, Chel-Jong Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.463 No.-

<P><B>Abstract</B></P> <P>Oxygen (O<SUB>2</SUB>) plasma treatment on germanium (Ge) surface was employed to depin Fermi-level in Al/n-type Ge interface. The Al contact to n-type Ge without and with O<SUB>2</SUB> plasma treatments for 1 and 2 min showed rectifying characteristics despite the low work function of Al, which could be associated with the Fermi-level pinning. An increase in O<SUB>2</SUB> plasma treatment time resulted in a decrease in Schottky barrier height along with the improvement of the homogeneity of Schottky interface. On the other hand, Al contact to O<SUB>2</SUB> plasma-treated n-type Ge for 3 min exhibited Ohmic behavior, implying the depinning of Fermi-level in Al/n-type Ge interface. A transition from rectifying to Ohmic behavior observed in Al/n-type Ge contact with O<SUB>2</SUB> plasma treatment for 3 min could be attributed to the more homogenous and stoichiometric formation of Ge-oxide layer. Such a high quality Ge-oxide layer effectively passivated unsatisfied surface states in Ge, which could be responsible for Fermi-level depinning of Ge.</P> <P><B>Highlights</B></P> <P> <UL> <LI> O<SUB>2</SUB> plasma treatment on Ge surface was employed to depin Fermi-level of Ge interface. </LI> <LI> Transition from Schottky to Ohmic behavior was observed in Al/n-type Ge with O<SUB>2</SUB> plasma treatment for 3 min. </LI> <LI> An increase in O<SUB>2</SUB> plasma treatment time led to the improved homogeneity of Schottky interface. </LI> <LI> More homogenous and stoichiometric Ge-oxide layer was formed after O<SUB>2</SUB> plasma treatment for 3 min. </LI> <LI> Ge surface passivation through Ge-oxide layer could be a main cause of depinning the Fermi-level of Ge. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effects of Ar-Plasma Treatment in Alkali-Decomposition of Poly(ethylene terephthalate)

Seo, Eun-Deock The Polymer Society of Korea 2003 Macromolecular Research Vol.11 No.5

The ablation effects of Ar-plasma treatment and alkali-decomposition behavior in NaOH solution of polyethylene terephthalate (PET) film were investigated. The modifications were evaluated by analysis of atomic force microscopy topographical changes, and by the measurement of decomposition yield in conjunction with heats of formation and electron densities of acyl carbon calculated by Parameterization Method 3 method. It has shown that the alkali-decomposition is hampered by plasma treatment and its decomposition yield is closely related with plasma treatment conditions such as exposure time to plasma. Plasma-treated PET films exhibited lower decomposition yield, compared to that of virgin PET. Increasing plasma exposure time contributes positively to decrease the decomposition yield. It has also shown that the topography of PET surface was affected by the base-promoted hydrolysis as well as Ar-plasma treatments. These behaviors are attributed to the decreased nucleophilicity of acyl carbon damaged by the ablation of Ar-plasma.