• Journal of the Semiconductor & Display Technology
• /
• v.19 no.3
• /
• pp.36-42
• /
• 2020

Silver nanowire (AgNW) random-meshes with high transmittance, low sheet resistance, and high oxidation stability and flexibility were fabricated using solution-based processes. The random-mesh structure was obtained by forming bubbles whose sizes and densities were controlled using a corona treatment of polyethylene terephthalate (PET) substrates. To reduce the sheet resistance of the fabricated AgNW electrode, a washing process using ethanol solution was performed. In addition, nickel (Ni) was coated on AgNW to improve resistance to oxidation. The effects of corona treatment and Ni-coating on the transmittance, sheet resistance, oxidation stability, and flexibility of the AgNW electrodes were investigated.

• Journal of the Korean institute of surface engineering
• /
• v.50 no.6
• /
• pp.455-459
• /
• 2017

The development of flexible transparent electrode has been paid attention for flexible electronics. In this study, we have developed transparent electrode based on silver nanowires with improved electrical property and stability through ion-beam treatment. The energetic particles of ion-beam could sinter junctions of each silver nanowires and etch out polyvinylpyrollidone(PVP) coated on silver nanowires. The sheet resistance of silver nanowire transparent electrode was reduced by 74%, and the resistance uniformity was increased about 3 times after exposure of ion beam. Moreover, the stability at $85^{\circ}C$ of temperature and 85% of relative humidity could be also improved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.8
• /
• pp.530-534
• /
• 2017

Transparent film heaters employing silver nanowires (Ag NWs) have attracted increasing attention because of their widespread applications. However, the low thermal resistance of Ag NWs limits the maximum operating temperature of the Ag NW film heater. In this study, Ag NW film heaters with high mechanical and thermal stability were successfully developed. The thermal power-out characteristics of the Ag NW heaters were investigated as a function of the Ag NW density. The results revealed that the prepared flexible Ag NW heater possessed high thermal stability over $190^{\circ}C$ owing to ZnO encapsulation. This indicates that the Ag NW film with excellent thermal stability have remarkably high potential for use as electrodes in film heaters operating at high temperatures.

• Proceedings of the Korea Contents Association Conference
• /
• 2018.05a
• /
• pp.561-562
• /
• 2018

디지털 중합효소연쇄반응(Digital PCR)은 3세대 PCR로 명명하며, 1세대인 일반 PCR과 2세대인 정량 PCR(Real-time PCR)의 단점을 보완하여 개발된 방법이다. Digital PCR System은 소량의 PCR 반응을 10만개 이상의 반응통(wall)에 적재하는 방식의 나노유체칩에서 쪼개어 증폭시킨 후, target DNA를 계수한다. Target DNA의 증폭 여부에 따라 positive(1)와 negative(0)로 digital signal처럼 받아들여 계수하고, 포아송 분포를 통해 target DNA의 copy를 계산해 최종적으로 샘플 microlitr당 Copy수로 결과 값을 확인할 수 있다. 본 연구에서는 종(種)이 다른 동물의 조직이 서로 섞여있을 때 사람의 조직을 탐색하는 방법으로 유전자 증폭을 할 경우, digital PCR의 유효성에 대해 증명하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.183.1-183.1
• /
• 2016

Due to the latest research trend toward wearable energy devices, transparent and stretchable supercapacitors which can sustain their performance even under physical deformation have steadily attracted huge attention. Despite the Ag NW is the most promising candidate for fabrication of transparent and stretchable electronics, the electrochemical instability interrupts its application to development of the energy device. Here, we introduce a transparent and highly stretchable supercapacitor made by Au-Ag core shell NW network percolation electrode. The Au-Ag core shell NW synthesized by a simple solution process not only shows excellent electrical conductivity but also greatly enhanced chemical and electrochemical stability compare to pristine Ag NW. These outstanding properties of the Au-Ag core shell NW are attributed both to the core Ag NW and the Au protecting sheath layer. The proposed Au-Ag core shell NW based supercapacitor exhibits optical transmittance with outstanding mechanical stability withstanding 60% strain without any decrease of the performance. The supercapacitors connected in series are charged and discharged stable in 30% strain turning on a red LED. These notable results demonstrate the potential of the Au-Ag core shell NW as a strong candidate for development of wearable energy devices.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2015.05a
• /
• pp.51-52
• /
• 2015

Organic light emitting diode (OLED) 나 organic photovoltaic device (OPV)와 같은 유기소자에 전극으로 쓰이고 있는 indium tin oxide (ITO)는 유연한 디바이스에 적용하기에는 유연성이 떨어진다는 문제가 있다. 이를 해결하기 위해서 ITO를 대체할 수 있는 CNT, Graphene, AgNWs, 전도성 고분자 등의 투명전극에 관한 연구가 활발히 진행되고 있다. 그러나 CNT, Grapene, 전도성 고분자는 여전히 전기적 특성이 좋지 못하기 때문에 차세대 투명전극으로 사용되기는 어려움이 있다. 반면에 AgNWs는 용액공정으로 제조 단가가 비교적 저렴하며, 높은 전기전도도 특성과 우수한 유연성을 가지는 투명 전극이기 때문에 많은 주목을 받고 있다. 그러나 NW-NW간의 접촉저항이 높아 전도성이 저하된다는 문제점과 Environmental stability가 좋지 못하다는 단점이 여전히 존재한다. 본 연구에서는 AgNW 전극 위에 플라즈마처리를 진행하여 AgNW의 전도성과 Stability를 향상시키고자하였다. 플렉서블한 PET기판위에 AgNW 전극을 Spray Coating하여 균일하게 전극을 형성하였고, 플라즈마 처리를 통해서 기판의 변형없이 AgNW의 저항을 45%이상 향상시켰으며, Stability 또한 아무것도 처리하지 않은 AgNW에 대비하여 2배 이상 향상된 것을 확인하였다.

• Journal of the Korean institute of surface engineering
• /
• v.55 no.3
• /
• pp.173-179
• /
• 2022

This study presents a roll-to-roll process which is capable of Ag nanowire (AgNW) transfer from polyethylene terephthalate (PET) film to polycarbonate (PC) film. We developed a roll-to-roll machine that consists of two film suppliers, a coater of photo-curable resin, a film laminator, an ultraviolet (UV) exposure unit, and a film winder to facilitate large-area electrode transfer between different flexible substates. Using the process, optimal fabrication condition was investigated by parametric experiments in terms of the UV exposure time, number of thermal cycling, and exposure time of high temperature and humidity. A fabricated AgNW on PC film showed sheet resistance of 52 Ω/sq and optical transmittance of approximately 80 % over a range of visible light.

• KSBB Journal
• /
• v.21 no.4
• /
• pp.317-323
• /
• 2006

This study focused on the availability of wastewater reclamation and reusing system as one of the alternatives against the global water shortage in near future, which system is composed of two treatment steps; first, wastewater is injected into upflow $A^2O$ biofilm process(anaerobic/anoxic/oxic) reactor filled with polyethylene fixed-media, and the effluent of 1st steps continuously passed through downflow nano silver sand filter. The pH of the effluent ranged from 7.39 to 8.06(average 7.84), the $COD_{Mn}$ was $8{\sim}18mg/L$(average 12.1 mg/L), and $BOD_5$ was $2.1{\sim}10.0mg/L$(average 4.9 mg/L), that met all the wastewater reclamation and reusing system criteria. Besides, the SS concentrations of the effluent which was $3{\sim}9mg/L$(average 4.95 mg/L) met the criteria(5 mg/L), showing 94.8% of average removal efficiency. The 99.1% of the average removal efficiency of the E-coliform did not met the criteria(Not detected), which indicates the needs for the following chlorine disinfection treatment with the residual chlorine concentration of above 0.2 mg/L. There are no bacteria on the sand surface coated by nano silver. The removal efficiency of T-N and T-P that could be included into the criteria in the future was 50.3% and 27.2% respectively.

• Korean Chemical Engineering Research
• /
• v.49 no.4
• /
• pp.475-479
• /
• 2011

Chitosan is a natural polymer that has many physicochemical(polycationic, reactive OH and $NH_2$ groups) and biological(bioactive, biocompatible, and biodegradable) properties. In this study, chitosan nanoparticles were prepared using poly-${\gamma}$-glutamic acid(${\gamma}$-PGA) as gelling agent. Nanoparticles were formed by ionic interaction between carboxylic groups in ${\gamma}$-PGA and amino groups in chitosan. Chitosan(0.1~1 g) was dissolved in 100 ml of acetic acid (1% v/v) at room temperature and stirred overnight to ensure a complete solubility. An amount of 0.1 g of ${\gamma}$-PGA was dissolved in 90 ml of distilled water at room temperature. Chitosan solution was dropped through needle into beaker containing ${\gamma}$-PGA solution under gentle stirring at room temperature. The average particle sizes were in the range of 80~300 nm. The prepared chitosan/${\gamma}$-PGA nanoparticles were used to examine their removal of several heavy metal ions($Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$, and $Ni^{2+}$) as adsorbents in aqueous solution. The heavy metal removal capacity of the nanoparticles was in the order of $Cu^{2+}$ > $Pb^{2+}$ > $Cd^{2+}$ > $Ni^{2+}$ > $Zn^{2+}$.

• Journal of Wetlands Research
• /
• v.20 no.3
• /
• pp.272-280
• /
• 2018

Existing toxicity assessment researches were rarely studied on assessment of the abnormal behavior that affecting survival. Therefore, the study used anti-predator response of amphibians larvae, based on behavioral understanding, to assess toxicity in fullerene nanowhisker(FNW) and fullerene nanowhisker-silver nanoparticle composites(FNW-Ag). The experiment was conducted by dividing the groups not exposed to nanomaterials and exposed to nanomaterials at five concentrations(FNW: $10{\mu}g/ml$, FNW: $100{\mu}g/ml$, FNW: $500{\mu}g/ml$ FNW-Ag: $10{\mu}g/ml$, FNW: $50{\mu}g/ml$). As a result, there were no differences in normal activity except those exposed to concentrations of FNW-Ag $50{\mu}g/ml$, but there were statistically significant differences in anti-predator response except those exposed to concentrations of FNW $10{\mu}g/ml$. That is, exposed of nanomaterials does not affect ordinary movements, but analyses based on behavioral understandings have shown that it has an influence on the anti-predator response. It is therefore considered necessary to have animal behavioral analysis method performed in the assessment of eco-toxic experiment.