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A Study on Adhesive for High Efficiency LED Light Using Nano Silver

  • Kim, Sungsu;Park, Hyunbum
    • International Journal of Aerospace System Engineering
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    • v.1 no.1
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    • pp.44-47
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    • 2014
  • This study proposes a development for the nano silver adhesive, which is applicable to high efficiency LED(light-emitting diode) light. The important issue of LED light is heat exhaust from LED. Generally, the middle area of LED light is increased up to 380K. Therefore, the bottleneck between LED chip and heat sink are caused by high temperature. In this work, the adhesive material between LED Chip and heat sink was newly developed for improvement of bottleneck. The nano silver was adopted to solve heat problem of chip on board package for LED light. In order to evaluate the performance of the nano silver adhesive, the thermal analysis was performed. Moreover both adhesive performance and heat exhaust were verified through the prototype test. From the experimental test results, it is found that the developed nano silver adhesive has the high performance.

Experimental Study on Performances and Economic Evaluations of the Qualify of the Material for Light Path (광도파로(光導波路)를 위한 재질의 성능과 경제적 평가를 위한 실험적 연구)

  • Pak, Ee-Tong;Lee, Kang-Ju;Park, Hae-Sung
    • Journal of the Korean Solar Energy Society
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    • v.27 no.3
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    • pp.175-179
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    • 2007
  • This experimental demonstration has successfully shown that it is possible to use direct sunlight for the illumination of deeper building zones using the material for light path system(light duct). Three kinds of reflectors which were 95% Silver vaporizing fixed, 85% Anodized and 85% Hot melted applied to evaluate and compare their performances each others. Also, these three kind of reflectors were compared in view point of economics. The most high performance was obtained in 95% Silver vaporizing fixed reflector hater than another reflectors of 85% Anodized reflector and 85% Hot melted reflector even though more high production cost in 95% Silver vaporizing fixed reflector. The rest two reflectors of 85% Anodized and 85% Hot melted $10{sim}15%$ less performance than 95% Silver vaporizing fixed reflector but their production cost were low than the production cost of 95% Silver vaporizing fixed reflector which identified very weak and light yellow color in the light.

Effect of Silver Nanoparticles with Indium Tin Oxide Thin Layers on Silicon Solar Cells

  • Oh, Gyujin;Kim, Eun Kyu
    • Applied Science and Convergence Technology
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    • v.26 no.4
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    • pp.91-94
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    • 2017
  • AThe effect of localized surface plasmon on silicon substrates was studied using silver nanoparticles. The nanoparticles were formed by self-arrangement through the surface energy using rapid thermal annealing (RTA) technique after the thin nanolayer of silver was deposited by thermal evaporation. By the theoretical calculation based on Mie scattering and dielectric function of air, indium tin oxide (ITO), and silver, the strong peak of scattering cross section of silver nanoparticles was found at 358 nm for air, and 460 nm for ITO, respectively. Accordingly, the strong suppression of reflectance under the condition of induced light of $30^{\circ}$ occurred at the specific wavelength which is almost in accordance with peak of scattering cross section. When the external quantum efficiency was measured using silicon solar cells with silver nanoparticles, there was small enhancement peak near the 460 nm wavelength in which the light was resonated between silver nanoparticles and ITO.

Study on A Laser-induced Photoredox Reaction for the Extraction of Precious Elements from Aqueous Solutions

  • Kyuseok Song;Hyungki Cha;Lee, Jongmin;Park, Jongsoo;Lee, Yong-Ill
    • Nuclear Engineering and Technology
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    • v.32 no.6
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    • pp.531-536
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    • 2000
  • The extraction of precious metals from aqueous solutions is performed by using a photoredox reaction with a Q-switched Nd:YAG laser. The metallic silver was efficiently precipitated and extracted from the silver nitrate solution by laser photolysis. An optimum reaction condition for silver extraction was determined by adjusting various experimental factors such as type of reducing agent, type of acids and reaction time. The composition of the reaction product was analyzed and it was identified as metallic silver, not other molecular types. The photoreaction of chromium(III) chloride in an acidic aqueous solution was also investigated. The 355 nm laser light was better suited for the reaction of silver nitrate as well as chromium(III) chloride in an acidic solution compared to the 532 nm light.

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Photo-sintering of Silaver Nanoparticles using UV-LED

  • Lee, Jaehyeong;Kim, Minha;Kim, Donguk
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.88.1-88.1
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    • 2015
  • In recent printed electronics technology, Photo-Sintering, a technique for sintering materials using a light source, has attracted attention as an alternative to time-consuming high-temperature thermal processes. The key principle of this technique is the selective heating of a strongly absorbent thin film, while preventing the heating of the transparent substrate by the light source. Many recent studies have used a flash lamp as the light source, and investigated the material-dependent effect of the width or intensity of the pulsed light. However, the flash lamp for sintering is not suitable for industry yet, because of needing too high power to sinter for a large scale. In energy-saving and large-scale sintering, LED technologies would be very useful in the near future. In this work, we investigated a sintering process for silver nanoparticles using UV-LED array. Silver nanoparticles in ink were inkjet-printed on a $1{\times}1cm$ area of a PET film and photo-sintered by 365 nm UV-LED module. A sheet resistance value as low as $72.6m{\Omega}/sq$ (2.3 - 4.5 times that of bulk silver) was obtained from the UV-LED sintering at 300 mW/cm2 for 50 min.

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Characterization and Stability of Silver Nanoparticles in Aqueous Solutions

  • Bac, L.H.;Gu, W.H.;Kim, J.C.;Kim, B.K.;Kim, J.S.
    • Journal of Korean Powder Metallurgy Institute
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    • v.19 no.1
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    • pp.55-59
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    • 2012
  • In this work, the silver nanoparticles have been synthesized by electrical explosion of wire in three liquid mediums: deionized water (DIW), polyvinylpyrrolidone (PVP) and sodium dodecyl benzene sulfonate (SDBS) solutions. Absorption in the UV-visible region of these suspensions was measured in the range of 300-800 nm. A surface plasmon peak was observed at ~400 nm in all suspensions in measured wavelength range. Particle size was analyzed by transmission electron microscope. It showed that the particles had nearly spherical shape in all samples. The average particle sizes prepared in DIW, PVP and SDBS solution were 37, 31 and 27 nm, respectively. Stability of the suspensions was estimated by multiple light scattering method. The presence of PVP and SDBS surfactants in the exploding medium resulted in enhanced stability of the silver suspensions.

Facile Synthesis of Silver Chloride Nanocubes and Their Derivatives

  • Kim, Seung-Wook;Chung, Haeg-Eun;Kwon, Jong-Hwa;Yoon, Ho-Gyu;Kim, Woong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2918-2922
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    • 2010
  • We demonstrate a facile route to synthesize silver chloride nanocubes and derivative nanomaterials. For the synthesis of silver chloride nanocubes, silver nitrate and hydrochloric acid were used as precursors in ethylene glycol, and poly (vinyl pyrrolidone) as a surfactant. Molar ratio of the two precursors greatly influenced the morphology and composition of the final products. As-synthesized silver chloride nanocubes showed size-dependent optical properties in the visible region of light, which is likely due to a small amount of silver clusters formed on the surface of silver chloride nanocubes. Moreover, we show for the first time that simple reduction of silver chloride nanocubes with different reducing reagents leads to the formation of delicate nanostructures such as cube-shaped silver-nanoparticle aggregates, and silver chloride nanocubes with truncated corners and with silver-nanograin decorated corners. Additionally, we quantitatively investigated for the first time the evolution of silver chloride nanocubes to silver chloride nanocubes decorated with silver nanoparticles upon exposure to e-beam. Our novel and facile synthesis of silver chloride related nanoparticles with delicately controlled morphologies could be an important basis for fabricating efficient photocatalysts and antibacterial materials.

Fabrication of Light Weighted Microwave Absorbers Using Silver-Coated Hollow Microspheres (은도금 중공미세구를 이용한 경량 전파흡수체의 제조)

  • Kim, Uk-Jung;Kim, Seon-Tae;Kim, Seong-Su;Gwon, Sun-Gil;An, Jun-Mo;Kim, Geun-Hong;Cheon, Chang-Hwan
    • Korean Journal of Materials Research
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    • v.11 no.11
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    • pp.941-946
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    • 2001
  • Conductive microspheres with a density of 0.2 g/cc were fabricated by electroless silver plating for application to the light-weighted microwave absorbers. The silver plating was conducted with the variation of plating conditions (sensitizing condition, $AgNO_3$, concentration, amount of reducing agent). Specimens have very low electro-resistivity. Under an optimum processing condition, conductive microspheres with uniform silver plating layer can be produced. Rubber-sphere composites were fabricated and their microwave absorbing properties were measured by HP8722D Network Analyzer. It was found that the lower the electrical resistance of microsphere, the better the microwave absorbing properties. Feasibility of microwave absorbers using this microspheres can be demonstrated with the result of microwave reflection loss of -15 dB and thickness of 1.44 mm.

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Natural Dyeing Absorption Properties of Chitosan and Nano Silver Composite Non-Woven Fabrics -Focus on Chrysanthemum Indicum Linn- (키토산/나노실버 복합섬유 혼방 부직포의 천연염색 염착특성 -감국을 중심으로-)

  • Hong, Byung-Suk;Chu, Young-Ju;Lee, Eun-Jin
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.5
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    • pp.775-783
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    • 2010
  • This study examines the dyeability, light fastness, washing fastness, and the antibacterial activity of chitosan and nano silver composite non-woven fabrics dyed with an extracted solution from Chrysanthemum Indicum Linn. The results show that an increase in the chitosan and nano silver percentage resulted in an increase in the $a^*$ values and $b^*$ values; however, the $L^*$ values decreased in the undyed condition. ${\Delta}E$ values of chitosan and nano silver composite non-woven fabrics were higher than cotton 100% non-woven fabrics in the dyed condition with an extracted solution from Chrysanthemum Indicum Linn, and mordant treatments influenced the chrominance change. In the dyed condition with an extracted solution from Chrysanthemum Indicum Linn, an increase in the percentage of chitosan and nano silver resulted in an increase of the K/S values. The dyeability of chitosan and nano silver composite non-woven fabrics increased by mordant treatments. The light fastness and washing fastness of the mordanted non-woven fabrics were better than the non-mordanted. For the antibacterial activity, the bacterial reduction rate of chitosan and nano silver composite non-woven fabrics was 99.9% to Staphylococcus aureus and Klebsiella pneumoniae.

The Research of Ni/Cu Contact Using Light-induced Plating for Cryatalline Silicom Solar Cells (결정질 실리콘 태양전지에 적용될 Light-induced plating을 이용한 Ni/Cu 전극에 관한 연구)

  • Kim, Min-Jeong;Lee, Soo-Hong
    • 한국태양에너지학회:학술대회논문집
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    • pp.350-355
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    • 2009
  • The crysralline silicon solar cell where the solar cell market grows rapidly is occupying of about 85% or more high efficiency and low cost endeavors many crystalline solar cells. The fabricaion process of high efficiency crystalline silicon solar cells necessitate complicated fabrication processes and Ti/Pd/AG contact, This metal contacts have only been used in limited areas in spite of their good srability and low contact resistance because of expensive materials and process. Commercial solar cells with screen-printed solar cells formed by using Ag paste suffer from loe fill factor and high contact resistance and low aspect ratio. Ni and Cu metal contacts have been formed by using electroless plating and light-induced electro plating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Copper and Silver can be plated by electro & light-induced plating method. Light-induced plating makes use the photovoltaic effect of solar cell to deposit the metal on the front contact. The cell is immersed into the electrolytic plating bath and irradiated at the front side by light source, which leads to a current density in the front side grid. Electroless plated Ni/ Electro&light-induced plated Cu/ Light-induced plated Ag contact solar cells result in an energy conversion efficiency of 16.446 % on 0.2~0.6${\Omega}$ cm, $20{\times}20mm^2$, CZ(Czochralski) wafer.

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