• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.487.1-487.1
• /
• 2014

현재 전 세계 태양광 시장의 주류를 이루는 단결정 실리콘 태양전지의 효율적 한계를 뛰어넘기 위하여 여러 가지 기술적 구조적 시도들이 이루어지고 있다. 그 중 기존의 피라미드 형태의 텍스쳐링 표면 대신 나노와이어 형상을 가지는 태양전지 개발이 주목을 받고 있다. 실리콘 웨이퍼 표면에 나노와이어가 수직 배열되어 있거나 텍스쳐링 표면에 나노와이어 형상이 있을 경우 SiNx가 증착된 피라미드 텍스쳐링 표면보다 반사도가 월등히 낮아져 light trapping을 기대할 수 있어 태양전지 개발에 응용하기 위한 나노와이어 형상 최적화에 본 연구의 목적이 있다. 실리콘 나노와이어 합성법에는 여러가지 방법들이 있으나 본 연구에서는 비교적 짧은 시간과 상온에서 공정이 이루어지는 무전해 식각법을 이용하여 실리콘 나노와이어를 합성하였다. 무전해 식각법은 은 이온과 실리콘 사이에서 일어나는 산화-환원 반응이 나노와이어 합성의 주요 기전이기 때문에 균일한 나노와이어를 형성하기 위하여 균일한 은 박막 형성과 적절한 반응시간이 요구된다. 본 연구에서는 반응시간을 조절하여 나노와이어의 길이 변화와 반사도의 변화를 FE-SEM과 UV-Vis-NIR spectroscopy를 통하여 관찰하였고 그 결과 나노와이어가 실리콘 웨이퍼 표면에 수직 배열되어 있는 형태와 텍스쳐링 표면에 나노와이어 형상이 있는 경우 SiNx가 증착된 피라미드 텍스쳐링 표면에 비해 월등히 향상된 반사율을 얻을 수 있었다.

• Applied Chemistry for Engineering
• /
• v.31 no.3
• /
• pp.299-304
• /
• 2020

Nanoparticles play an important role as a catalyst in many chemical syntheses. Colloidal nanoparticles were usually synthesized with reducing, capping, and shape directing agents which induce surface poisoning of catalysts. A new green synthesis for silver nanoparticles was developed by utilizing less additives which could be a hazardous waste. A crystallization technique was employed to reduce the amount of reducing and capping agents during synthesis resulting in less surface poisoning of the nanoparticle. The synthesized Ag nanoparticles using monosaccharides and disaccharides as reducing agents could be used as a catalyst for the redox reaction of resazurin and the mechanism of the reaction using Ag nanoparticles was studied.

• Membrane Journal
• /
• v.20 no.2
• /
• pp.169-172
• /
• 2010

Silver ions of poly(vinyl chloride)-g-poly(styrene sulfonic acid) (PVC-g-PSSA) graft copolymer were reduced to form silver nanoparticles under thermal condition ($80^{\circ}C$). We were successful in synthesizing silver nanoparticles with various morphologies by changing reaction time. At short reaction times (~1 h), silver nanoparticles with 5 nm in size were formed without disrupting a microphase-separated structure of graft copolymer. At medium reaction times (~5 h), silver nanoparticles were aggregated to form large clusters ranging 30~50 nm in size. At much longer reaction times (~18 h), hurricane-like silver clusters were observed due to strong particle aggregation.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.16 no.6
• /
• pp.250-255
• /
• 2006

The synthesis and characterization of silver colloidal nanoparticles by chemical reduction of silver ions in aqueous $AgNO_3$ using sodium borohydride $(NaBH_4)$ as the reducing agent are described. The experimental conditions for aggregation and paricle size of nanosilver particles in water is investigated in terms of concentration of $NaBH_4$, reaction temperature, dropping rate of $AgNO_3$ and concentration of laponite. Stable nanosilver sol is obtained at three molar ratio of $NaBH_4/AgNO_3$ in conditions of without laponite. The size of nanosilver particles is increased as the reaction temperature is increased. The large size of nanosilver sol is obseved as the dropping rate of $AgNO_3$ is increased due to the aggregation of initial high local concentration of nanosilver particles. Stable nanosilver sol at high temperature $(>\;100^{\circ}C)$ can be prepared when laponite is used as protective colloid.

• Journal of the Korean Chemical Society
• /
• v.51 no.2
• /
• pp.136-140
• /
• 2007

By using the discrete-dipole approximation, we computed the extinction spectrum of a gold-silver alloy nanoparticle. We have examined how the surface plasmon resonance changes with respect to the variation in the composition of the alloy particle. As the fraction of silver increases for a 10nm particle, the peak position of the extinction spectrum blue-shifts linearly. The intensity of the peak however increases exponentially with increasing the silver fraction. These results are in accord with the previous experimental results.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.32 no.12
• /
• pp.1848-1856
• /
• 2008

In order to enhance the functionality of a cotton fabric actually used as the clothing material for patients, the fabrics are treated with chitosan/nanosilver mixed solution. The nanosilver has excellent biocompatibility, not causing an environmental pollution as a natural polymer, provides expectation of an additional performance, does not harm human beings, and shows a strong antibacterial activity even in a small amount, and supplements chitosan, which is disadvantaged if used alone for fabric treatment. This study evaluates functional improvement of the clothing material for patients and observes through hygienic characteristics which are the most important function. In antibacterial activity of the fabrics treated with chitosan/nanosilver mixed solution against Staphylococcus aureus, higher ratio of chitosan was observed to achieve better antibacterial activity. In antibacterial activity against Klebsiella pneumoniae, higher ratio of nanosilver was observed to achieve better activity. Regarding laundry durability of antibacterial activity after repeated laundering, activity against Staphylococcus aureus was little reduced, but was greatly lowered against Klebsiella pneumoniae. Deodorization activity was excellent as the mixed ratio of chitosan was increased, and air permeability, moisture permeability and moisture regain were reduced as the mixed ratio of nanosilver was increased.

• KOREAN POULTRY JOURNAL
• /
• v.42 no.9
• /
• pp.130-133
• /
• 2010

경기도 안성에서 일일 15,000여개 유정란을 생산하는 농장이 있다. 해샘찬농장 김종찬 사장은 20여년간 양계사료 약품업체에 근무해왔고, 3년 전부터는 귀농을 선택해 건강한 계란을 생산하고 있다. 김종찬 사장은 과학사료 근무 당시 은나노사업부서 멤버로 활동했고, 현재는 천연항생제인 '은나노'파우더를 첨가한 사육방식으로 유정란 생산에 참여하고 있다. 이번호에는 무항생제 인증을 받아 건강한 유정란을 생산하는 해샘찬농장을 소개하고자 한다.

• Membrane Journal
• /
• v.21 no.1
• /
• pp.39-45
• /
• 2011

An amphiphilic graft copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly(styrene sulfonic acid) (PSSA) side chains (PVC-g-PSSA) was synthesized via atom transfer radical polymerization (ATRP). This polymer electrolyte membrane was ion-exchanged to Ag ions by immersing in 10 wt% $AgNO_3$ aqueous solution and templated the growth of Ag nanoparticles by a reducing agent. The formation of Ag nanoparticles was confirmed using UV-visible spectroscopy and X-ray diffraction (XRD). Transmission electron microscopy (TEM) revealed that utilization of $NaBH_4$ was the most effective in the formation of Ag nanoparticles with 10~15 nm in size. The formation of Ag nanoparticles was also strongly affected by the concentration of reducing agent and reduction time.

• Polymer(Korea)
• /
• v.35 no.5
• /
• pp.390-394
• /
• 2011

Effects of silver nanoparticles on the polymerization rate and morphology of poly(vinyl acetate) (PVAc)/silver microspheres prepared by suspension polymerization of VAc were investigated. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and atomic absorption spectrometry were used to characterize the morphology and properties of the PVAc/silver microspheres. Due to the change of hydrophilicity of silver nanoparticles, appearance of the microspheres having golf ball-like convave surfaces was observed. Under controlled concentration of surfactant, PVAc/silver microspheres with various hollow structures were synthesized. In the case of silver nanoparticles modified by surfactant, the polymerization rate increased slightly. PVAc/silver microspheres with a conversion up to 80% were prepared via suspension polymerization.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2013.05a
• /
• pp.166-166
• /
• 2013

유체 플라즈마 공정은 금속 나노입자를 제조하는데 있어서 혁신적이고 친환경적인 공정 방법의 하나이다. 본 연구에서는 유체 플라즈마 공정을 통해 젤라틴 기지재 내에 은 나노입자를 합성하였고, 합성 된 용액은 동결건조를 통해 3D scaffold 형태의 생체복합체로 제조하였다. 이렇게 제조된 생체복합체의 물리적 특성 및 생물학적 특성 평가를 통해 생체복합체의 효율성과 항균 효과가 뛰어남을 확인하였다.