• 한국정밀공학회지
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• 제31권8호
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• pp.737-742
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• 2014

This paper reports a customized silver ink and its inkjet printing process on a cellulose electro-active paper (EAPap). To synthesize a silver ink, silver nanoparticle is synthesized from silver nitrate, polyvinylpyrrolidone and ethylene glycol, followed by adding a viscosifier, hydroxyethyl-cellulose solution, and a surfactant, diethylene glycol. The silver ink is used in an inkjet printer (Fujifilm Dimatix DMP-2800 series) to print silver electrodes on cellulose EAPap. After printing, the electrodes are heat treated at $200^{\circ}C$. The sintered electrodes show that the thickness of the electrodes linearly increases as the number of printing layers increases. The electrical resistivity of the printed electrodes is $23.5{\mu}{\Omega}-cm$. This customized ink can be used in inkjet printer to print complex electrode patterns on cellulose EAPap to fabricate flexible smart actuators, flexible electronics and sensors.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.730-732
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• 2007

We fabricated a coplanar type organic thin-film transistors using ink-jet printed silver source/drain electrodes and ${\alpha},{\omega}-dihexylquaterthiophene$ (DH4T) which is an active layer. Use of ink-jet printed silver nanoparticle-based metal electrode assists the energetic mismatch with p-type organic semiconductor via modification of their interfacial properties to enable ohmic contact formation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.226.2-226.2
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• 2014

나노 사이즈의 Ni 입자 ink를 제조하고 이를 전기수력학 인쇄공정에 적용하기 위하여 잉크의 유변학적 특성 및 최적 물성 발현을 위한 인쇄공정에 대한 연구를 진행하였다. Ni 잉크의 점도 및 증발거동 조절을 통해 전기수력학 인쇄공정을 최적화 하는 연구를 수행하였다. Ni 나노입자 잉크의 초기 점도가 낮고 인쇄성이 확보되지 않아 잉크내 응집성을 향상시켜주기 위한 다양한 additive들을 선정하여 전기수력학에 적합한 잉크 물성 확보에 비중을 두고 실험을 진행 하였다. 터비스캔을 사용하여 제조된 잉크 안정성에 대한 연구를 진행하였다. 다양한 인쇄공정 변수의 최적화를 통해 미세선폭 (< 20 um)이 가능한 전기수력학 인쇄공정을 확립하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.89.2-89.2
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• 2007

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1712-1713
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• 2011

Inkjet technology have many merits in plenty of industrial applications. However, deposited droplet has a very critical issue that is coffee ring effect, for the application to an industrial manufacturing process. To remove the coffee ring effect, the effect of thermal treatment conditions on shapes of inkjet printed silver patterns were investigated in various surface condition. The surface changes were characterized by the contact angle measurement. Droplets from a 50 ${\mu}m$ nozzle were printed on the substrate after optimizing the ejection of individual droplets. Ink with a high boiling point of main solvent results in coffee ring effect. This result implies that the dominant factor that determines the shape of droplet is the drying conditions of main solvent of silver nanoparticle colloidal ink. As a results, selecting a proper thermal treatment conditions is very crucial for better shapes of inkjet printed silver nanoparticle colloidal patterns.

• 한국생산제조학회지
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• 제24권1호
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• pp.135-139
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• 2015

We present a fine patterning method of conductive lines on polyimide (PI) and glass substrates using silver (Ag) nanoparticles based on laser scanning. Controlled laser irradiation can realize selective sintering of conductive ink without damaging the substrate. Thus, this technique easily creates fine patterns on heat-sensitive substrates such as flexible plastics. The selective laser sintering of Ag nanoparticles was managed by optimizing the conditions for the laser scan velocity (1.0-20 mm/s) and power (10-150 mW) in order to achieve a small gap size, high electrical conductivity, and fine roughness. The fabricated electrodes had a minimum channel length of $5{\mu}m$ and conductivity of $4.2{\times}10^5S/cm$ (bulk Ag has a conductivity of $6.3{\times}10^5S/cm$) on the PI substrate. This method was used to successfully fabricate an organic field effect transistor with a poly(3-hexylthiophene) channel.

• 한국재료학회지
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• 제17권9호
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• pp.453-457
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• 2007

Interest in use of ink-jet printing for pattern-on-demand fabrication of metal interconnects without complicated and wasteful etching process has been on rapid increase. However, ink-jet printing is a wet process and needs an additional thermal treatment such as an annealing process. Since a metal ink is a suspension containing metal nanoparticles and organic capping molecules to prevent aggregation of them, the microstructure of an ink-jet printed metal interconnect 'as dried' can be characterized as a stack of loosely packed nanoparticles. Therefore, during being treated thermally, an inkjet-printed interconnect is likely to evolve a characteristic microstructure, different from that of the conventionally vacuum-deposited metal films. Microstructure characteristics can significantly affect the corresponding electrical and mechanical properties. The characteristics of change in microstructure and electrical resistivity of inkjet-printed silver (Ag) films when annealed isothermally at a temperature between 170 and $240^{\circ}C$ were analyzed. The change in electrical resistivity was described using the first-order exponential decay kinetics. The corresponding activation energy of 0.44 eV was explained in terms of a thermally-activated mechanism, i.e., migration of point defects such as vacancy-oxygen pairs, rather than microstructure evolution such as grain growth or change in porosity.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.114.1-114.1
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• 2011

Electrical sintering of the front electrode for crystalline silicon solar cells was performed applying a constant DC current to the printed lines. Conducting lines were printed on glass substrate by a drop-on-demand (DOD) inkjet printer and silver nanoparticle ink. Specific resistance and microstructure of sintered silver lines and were measured with varying DC current. To find the relation between temperature increase with changing applied current and specific resistance, temperature elevation was also calculated. Sintering process finished within a few milliseconds. Increasing applied DC current, specific resistance decreased and grain size increased after sintering. Achieved minimum specific resistance is approximately 1.7 times higher than specific resistance of the bulk silver.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1494-1495
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• 2009

Thin Film Transistor(TFT) having CIS (CuInSe) semiconductor layer was fabricated and characterized. Heavily doped Si was used as a common gate electrode and PECVD Silicon nitride ($SiN_x$) was used as a gate dielectric material for the TFT. Source and drain electrodes were deposited on the $SiN_x$ layer and CIS layer was formed by a direct patterning method between source and drain electrodes. Nanoparticle of CIS material was used as the ink of the direct patterning method.

• 한국기계가공학회지
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• 제21권4호
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• pp.107-113
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• 2022

At present, it is possible to manufacture electrodes down to several micrometers (~ ㎛) using inkjet printing technology owing to the development of precision ejection heads. Inkjet printing technology is also used in the manufacturing of bio-sensors, electronic sensors, and flexible displays. To reduce the difference between the electrode design/simulation performance and actual printing pattern performance, it is necessary to analyze and optimize the processable area of the ink material, which is a fluid. In this study, process optimization was conducted to manufacture an IDE pattern and fabricate an impedance sensor. A total of 25 IDE patterns were produced, with five for each lamination process. Electrode line width and height changes were measured by stacking the designed IDE pattern with a nanoparticle-based conductive ink multilayer. Furthermore, the optimal process area for securing a performance close to the design result was analyzed through impedance and capacitance. It was observed that the increase in the height of stack layer 4 was the lowest at 4.106%, and the increase in capacitance was measured to be the highest at 44.08%. The proposed stacking process pattern, which is optimized in terms of uniformity, reproducibility, and performance, can be efficiently applied to bio-applications such as biomaterial sensing with an impedance sensor.