• 한국정밀공학회지
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• 제24권5호
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• pp.89-96
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• 2007

Inkjet printing has become one of the most attractive manufacturing techniques in industry. Especially inkjet printing technology will soon be part of the PCB (Printed Circuit Board) fabrication processes. Traditional printing on PCB includes screen printing and photolithography. These technologies involve high costs, time-consuming procedures and several process steps. However, by inkjet technology manufacturing time and production costs can be reduced, and procedures can be more efficient. PCB manufacturers therefore willingly accept this inkjet technology to the PCB industry, and are quickly shifting from conventional to inkjet printing. To produce the printed circuit board by the inkjet technology, it must be harmonized with conductive nano ink, printing process, system, and inkjet printhead. In this study, micro patterning of conductive line has been investigated using the piezoelectric printhead driven by a bipolar voltage signal is used to dispense 20-40 ${\mu}m$ diameter droplets and silver nano ink which consists of 1 to 50 nm silver particles that are homogeneously suspended in an organic carrier. To fabricate a conductive line used in PCB with high precision, a printed line width was calculated and compared with printing results.

• Transactions on Electrical and Electronic Materials
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• 제16권4호
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• pp.212-220
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• 2015

We investigated nanotextured Si solar cells using the silver-assisted chemical etching process. The nanotexturing process is very sensitive to the concentration of chemical etching solution. The high concentration process results in a nanowire formation for the nanosurfaces and causes severe surface damage to the top region of the micropyramids. These nanowires show excellent light absorption in photoreflectance spectra and radiative light emission in photoluminescence spectra. However, the low concentration process forms a nano-roughened surface and provides high minority carrier lifetimes. The nano-roughened surfaces of the samples show the improved electrical cell properties of quantum efficiency, conversion efficiency, and cell fill factor due to the reduction in the formation of the over-doped dead layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.511-511
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• 2007

Low-emissivity (low-e) coatings with visible transparency have attracted increased interest m reducing heat radiation loss through window panes from ecological and sustainable aspects. $TiO_2$-silver transparent thin films for low-e have good properties for UV and IR blocking as well as photocatalyst compared to that with commercial UV blocking films such as fluorine doped oxide (FTO), antimony doped tin oxide (ATO), etc. In this study, transparent $TiO_2$-silver thin films were prepared by successive ink-jet printing of commercial nano silver and $TiO_2$ sol. The $TiO_2$ sol, as ink for ink-jet printing, were synthesized by hydrothermal process in the autoclave externally pressurized with $N_2$ gas of 200 bar at $120^{\circ}C$ for 10 hrs. The synthesized $TiO_2$ sols were all formed with brookite phase and their particle size was several to 30 nm. At first nano sized silver sol was coated on glass substrate, after that $TiO_2$ sol was coated by ink-jet printing. With increasing coating thickness of $TiO_2$-silver multilayer by repeated ink-jet coating, the absorbance of UV region (under 400nm) and IR region (over 700nm) also increase reasonably, compared to that with commercial UV blocking films.

• 대한기계학회논문집A
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• 제32권9호
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• pp.754-760
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• 2008

A two-photon induced photoreduction process suggests a possibility for fabricating complicated metallic microstructures which can be applied to 3-D micro-circuits and optical devices, etc. The process employs the photoreduction of silver ions in a metallic solution which is composed of metallic salt ($AgNO_3$) and watersoluble polymer ((poly(4-styrenesulfonique acid) 18wt. % in $H_2O$, $(C_8H_8O_3S)_n$)). In this process, the improvement of the resolution and the uniformity of fabricated metallic structures are important issues. To address these problems, continuous forming window (CFW) is obtained from a parametric study on the conditions of laser power and scanning velocity and the direct seed generation (DSG) method is proposed. Silver nano particles are uniformly generated in a metallic solution through the DSG method, which enables the decrease of a laser power to trigger the photoreduction of silver ions as well as the increase of metal contents in a metallic solution. So the two-photon induced photoreduction property of a metallic solution is improved. Through this work, precise silver patterns are fabricated with a minimum line width of 400 nm.

• KSBB Journal
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• 제21권4호
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• pp.317-323
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• 2006

본 연구는 다가올 물 부족에 따른 하나의 대안으로서 중수도 시스템에 초점을 맞추어, 생활오수를 이용하여 혐기/무산소/호기조의 $A^2O$ 생물막 공법으로 구성된 상향류식 고정상 담체 반응기로 처리한 오수를 하향류식 은나노 모래여과 반응기에 다시 연속 통과시켜 이중 처리하여 얻은 처리수를 중수도에 활용이 가능하지에 대하여 연구하였다. 이중 공정 후 배출수의 pH는 $7.39{\sim}8.06$(평균 7.84) 범위이었고, $COD_{Mn}$은 $8{\sim}18mg/L$(평균 12.1 mg/L), $BOD_5$는 $2.1{\sim}10mg/L$(평균 4.9 mg/L)로 중수도 수질 기준에 적합하였다. SS는 $3{\sim}9mg/L$의 범위로 평균 농도가 4.95 mg/L를 나타내면서 SS 제거율이 94.8%로 대부분 법적 기준치 5 mg/L 이하로 처리되어 가능성을 보여 주었다. 대장균군 수의 평균 제거율이 99.1%이었으며, 배출수의 평균 대장균 군수는 65 MPN/100mL이 검출되었으나 중수도 수질 기준에는 불검출로 되어 있으므로 완벽한 제거를 위해서는 0.2 mg/L 이상의 결합잔류염소의 양을 고려한 염소 처리를 하여야 한다. SEM 사진으로부터 은모래 표면에서는 박테리아가 존재하지 않음을 알 수 있었다. 이 외에 중수도 수질 기준에 포함될 가능성이 있는 총질소 및 총인의 제거율은 각각 50.3%와 27.2%이었다.

• 대한기계학회논문집B
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• 제29권12호
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• pp.1329-1334
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• 2005

Synthesis of silver nanoparticles by the supersonic nozzle expansion method with corona discharge ions was investigated. Corona discharge ions functioned as seeds for heterogeneous nucleation in the silver nanoparticles formation process and provided silver nanoparticles with electronic repulsive force that prevents aggregation of the particles. For ion ejecting, we used sonic-jet corona discharger. Upon application of the corona discharge ions, the mean diameter of the produced particles was decreased from 12.54 to 6.22nm and the standard deviation was decreased from 5.02 to 3.34nm. In addition, the agglomeration of silver nanoparticles was reduced.

• 한국분무공학회지
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• 제17권1호
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• pp.20-26
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• 2012

Inkjet printing is one of the direct writing technologies and is able to form a pattern onto substrate by dispensing droplets in desired position. Also, by inkjet technology manufacturing time and production costs can be reduced, and procedures can be more efficient. To form a metal pattern, it must be harmonized with conductive nano ink, printing process, sintering, and surface treatment. In this study, micro patterning of conductive line has been investigated using the piezoelectric printhead driven by a bipolar voltage signal is used to dispense $20-40{\mu}m$ diameter droplets and silver nano ink which consists of 50 nm silver particles. In addition, hydrophobic treatment of surface, overlap printing techniques, and sintering conditions with changing temperature and times to achieve higher conductivity.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.215-221
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• 2017

The electroless plating process largely consists of substrate cleaning, seed formation (activator formation), and electroless plating. The most widely used activator in the seed formation step is Pd, and Sn ions are used to facilitate the formation of this Pd seed layer. This is problematic because the Sn ions interfere with the reduction of Cu ions during electroless plating; thus, the Sn ions must be removed by a hydrochloric acid cleaning process. This method is also expensive due to the use of Pd. In this study, Cu electroless plating was performed by forming a seed layer using a silver nanosol instead of Pd and Sn. The effects of the Ag nanosol concentration in the pretreatment solution and the pretreatment time on the thickness and surface morphology of the Cu layer were investigated. The degrees of adhesion to the substrate were similar for the electroless-plated Cu layers formed by conventional Pd activation and those formed by the Ag nanosol.

• 한국통신학회논문지
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• 제42권4호
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• pp.716-722
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• 2017

본 논문에서는 은 나노 분말과 카본 잉크를 이용하여 13.56 MHz에서 동작하는 완전 인쇄형 NFC 태그를 설계 및 제작하였다. 제안된 NFC 태그는 50 pF의 내부 커패시턴스를 갖는 NFC 태그 IC에 적용하기 위해서, $2.74{\mu}H$의 인덕턴스를 갖는 원형 코일을 PI 필름 위에 설계하였으며, 전통적인 회로 제작 방식인 PCB 제조 공정에 비해 대면적 및 대량 생산, 저비용, 친환경공정 등의 장점을 가진 인쇄 전자 기술인 스크린 프린팅 기법을 이용하여 제작하였다. 제안된 구조는 단일 층으로 구현된 원형 코일, 코일 외곽과 중심부 사이에 칩 실장을 위한 점퍼 패턴, 그리고 코일과 점퍼 패턴과의 절연을 위한 절연 패턴으로 구성되어 있으며, 은 나노 분말과 카본 잉크를 이용하여 전도성 패턴과 절연 패턴을 중첩 인쇄하여 구현하였다. 본 논문에서 제안된 NFC 태그의 성능 검증을 위해 인쇄선폭, 두께, 선저항, 밀착력 그리고 환경 신뢰성 평가 등을 수행하였으며, 완전 인쇄형 제작 방식 기반 NFC 태그의 적합성을 확인하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.238.1-238.1
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• 2011

본 연구에서는 non-contact deposition method의 일환인 ESD (electroctatic deposition)의 박막공정을 이용하여 Conductive layer 위에 Gold nanoparticles 및 Silver nanoparticles 등 organic/inorganic nano particle conductive ink system의 단분산 2D 박막을 제조를 연구하였다. ESD head를 통해 여러가지 organic / inorganic nano particle conductive ink system을 Deposition하였으며 분산도가 높고 균일한 단분산의 2차원 박막 구조를 얻을 수 있었으며, 전도성 PEDOT과의 Hybridization을 통해 균일상의 표면 Morphology를 갖는 고 전도성 투명 필름을 제작하였다. ESD technique를 이용하는 박막공정 기술은 나노입자 및 나노구조물의 박막화 패턴화를 포함하는 새로운 Deposition 기술로써 이를 응용하여 금속 나노입자의 2차원의 패턴화된 박막 구현을 통해 유기반도체 및 전자소자에의 응용성을 증거할 수 있었다.