• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.396-401
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• 2014

Nanomaterials have been widely used in many fields. This study investigates the effects of metal oxide nanoparticles (CuO, NiO, $TiO_2$, $Fe_2O_3$, $Co_3O_4$, ZnO) on germination and germination index (G.I.) of seeds, Lactuca and Raphanus. Under aqueous exposure, CuO on Lactuca shows the most significant impacts on activities compared to others, showing $EC_{50s}$ for germination and G.I. as 0.46 mg/L and 0.37%, respectively. The effects of nanoparticle phytotoxicity on seed Lactuca was much higher than that of Raphanus. In general, the toxicities on seed germination and germination index were as following orders : CuO > ZnO > NiO ${\gg}$ $TiO_2$, $Fe_2O_3$, $Co_3O_4$. No measurable inhibition was observed at 1,000 mg/L (maximum exposure concentration) of $TiO_2$, $Fe_2O_3$, $Co_3O_4$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.153-153
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• 2012

자연계에는 다양한 생물체들의 표면 구조가 특수한 기능을 갖는 형태로 되어 있다. 이와 같이 특수한 기능을 갖는 생물체들의 표면 구조는 일반적으로 화학적 조성과 표면의 더불어 나노와 마이크로 구조가 혼합되어 있는, 이른바 hierarchical 구조를 보인다. 그 중에서도 표면 초소수성 특성을 보이는 연잎의 표면과 같은 hierarchical 구조는 self-cleaning effect 등의 기능성 표면 제작에 활용이 가능하여 이를 모사하기 위한 연구가 활발히 진행중에 있다. 이에 본 연구에서는 연잎과 같은 초소수성을 띄는 ZnO nano-in-micro hierarchical 구조를 저온 공정을 통하여 다양한 기판에 제작하였다. 이를 위하여 ZnO 나노 입자 분산 레진을 제작하였고 UV imprinting 과 수열합성법을 통하여 마이크로 패턴 상부에 ZnO 나노 입자가 형성된 ZnO nano-in-micro hierarchical 구조를 형성하였다. 제작된 ZnO hierarchical 구조의 젖음 특성은 표면 접촉각이 $160^{\circ}C$이상인 초소수성을 보였으며, 제작 공정에는 고온의 열처리가 수반되지 않아 PET film 등 다양한 기판에 ZnO hierarchical 구조를 제작할 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.6.1-6.1
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• 2009

최근 신 재생 에너지에 대한 관심이 고조되고 있으며 특히 태양전지는 차세대 대체에너지로 많은 연구 개발이 이루어지고 있다. 현재 태양전지 시장은 벌크실리콘 태양전지가 주를 이루고 있으나, 박막형, 유기물, 염료감응형 등 다양한 차세대 태양전지가 개발되고 있다. 차세대 태양전지는 글래스나 폴리머 기판위에 형성된 전극을 바탕으로 하여 다양한 형태의 태양전지가 형성되기 때문에 태양전지용 투명도전성 산화물 전극에 대한 중요성이 증가하고 있다. 예를 들어 실리콘 박막형 태양전지의 경우 수소 플라즈마 분위기 안정성 때문에 ZnO:Al 전극이 개발, 적용되고 있다. 이밖에도 ZnO는 나노입자, 나노로드 등의 다양한 형태를 기반으로 유기물 및 염료감응형 태양전지 전극으로 적용되고 있다. 본 연구에서는 전기화학적 방법을 이용해 나노입자, 나노로드, 나노 sheet 등 다양한 형태의 ZnO 나노구조를 형성한 후, 태양전지 적용을 위한 전기적, 광학적 특성을 분석하였다. 3차원 형태의 ZnO sheet 전극은 90% @ 550 nm 가 넘는 우수한 광특성 (Haze value)을 보였으며, 염료감응형 태양전지에 적용되었을 경우 2차원 형태의 ZnO 전극에 비해 Jsc 값이 2.5배 이상 향상되었다.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.617-621
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• 2009

Zinc oxide (ZnO) nanorods were grown on the pre-oxidized silicon substrate with the assistance of Au and the fluorine-doped tin oxide (FTO) based on the catalysts by vapor-liquid-solid (VLS) synthesis. Two types of ZnO powder particle size, 20nm, $20{\mu}m$, were used as a source material, respectively The properties of the nanorods such as morphological characteristics, chemical composition and crystalline properties were examined by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field-emission scanning electron microscope (FE-SEM). The particle size of ZnO source strongly affected the growth of ZnO nanostructures as well as the crystallographic structure. All the ZnO nanostructures are hexagonal and single crystal in nature. It is found that $1030^{\circ}C$ is a suitable optimum growth temperature and 20 nm is a optimum ZnO powder particle size. Nanorods were fabricated on the FTO deposition with large electronegativity and we found that the electric potential of nanorods rises as the ratio of current rises, there is direct relationship with the catalysts, Therefore, it was considered that Sn can be the alternative material of Au in the formation of ZnO nanostructures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.222-227
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• 2018

$Zn_{1-x}Co_x$ Zeolitic Imidazolate Framework (ZIF) (x = 0~0.05) were prepared by the co-precipitation of $Zn^{2+}$ and $Co^{2+}$ using 2-methylimidazole, which were converted into pure and Co-doped ZnO nanoparticles by heat treatment at $600^{\circ}C$ for 2 h. Homogeneous Zn/Co ZIFs were achieved at x < 0.05 owing to the strong coordination of the imidazole linker to $Zn^{2+}$ and $Co^{2+}$, facilitating atomic-scale doping of Co into ZnO via annealing. By contrast, heterogeneous Zn/Co ZIFs were formed at $x{\geq}0.05$, resulting in the formation of $Co_3O_4$ second phase. To investigate the potential as high-performance gas sensors, the gas sensing characteristics of pure and Co-doped ZnO nanoparticles were evaluated. The sensor using 3 at% Co-doped ZnO exhibited an unprecedentedly high response and selectivity to trimethylamine, whereas pure ZnO nanoparticles did not. The facile, bimetallic ZIF derived synthesis of doped-metal oxide nanoparticles can be used to design high-performance gas sensors.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.173-180
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• 2004

Nano sized ZnO particle as 20-30nm applies for material, pigments, rubber additives, gas sensors, varistors, fluorescent substance as well as new material such as photo-catalyst, sensitizer, fluorescent material. ZnO with a particle size in the range 20-30nm has provided to be an excellent UV blocking material in the cosmetics industry, which can be used in sunscreen product to enhance the sun protection factor and natural makeup effect. But pure ZnO particles application limits for getting worse wearing feeling. We make high-functional inorganic-composite that coated with nano-ZnO on the plate-type particle such as sericite, boron nitride and bismuthoxychloride. In this experiment, we synthesized composite powder using hydrothermal precipitation method. The starting material was ZnCl$_2$ Precipitation materials were used hexamethylenetetramine(HMT) and urea. We make an experiment with changing as synthesis factors that are concentrations of starting material, precipitation materials, nuclear formation material, reaction time, and reaction temperature. We analyzed composite powder's shape, crystallization and UV-blocking ability with FE-SEM, XRD, FT-IR, TGA-DTA, In vitro SPF test. The user test was conducted by product's formulator. In the results of this study, nanometer sized ZnD was coated regardless of the type of plate-powder at fixed condition range. When the coated plate-powders were applied in pressed powder product, the glaze of powder itself decreased, but natural make-up effect, spreadability, and adhesionability were increased.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.49-53
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• 2022

In this study, quantum dot light-emitting diodes (QLEDs) of the optimized EL performance with a radio frequency (RF) sputtered Zn_0.85Mg_0.15O thin film as an electron transport layer (ETL). In typical QLEDs, ZnO nanoparticles (NPs) are widely used materials for ETL layer due to their advantages of high electron mobility, suitable energy level and easy capable of solution processing. However, the instability problem of solution-type ZnO NPs has not yet been resolved. To solve this problem, ZnMgO thin film doped with 15% Mg of ZnO was fabricated by RF sputtering and optimized for the device applied as an ETL. The QLEDs of optimized ZnMgO thin film exhibited a maximum luminance of 15,972 cd/m² and a current efficiency of 7.9 cd/A. Efficient QLEDs using sputtering ZnMgO thin film show the promising results for the future display technology.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.197-197
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• 2009

전기도금방법으로 여러형태의 ZnO 나노구조를 ITO/glass 위에 전착하였다. 그 중 sheet 형태의 ZnO 나노구조 위에 $TiO_2$와 CdSe 나노입자를 전기화학적 방법으로 전착하여 유 무기 복합태양전지 및 염료감응형 태양전지의 anode로 적용하였다. 동일조건 하에서 ZnO-CdSe 형태의 전극을 사용하였을 때 Jsc, Voc 값이 상대적으로 다른 전극에 비해 증가하였다.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.274-279
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• 2006

To synthesize ZnO colloidal solution by a sol-gel process, zinc acetate ($C_{4}H_{6}O_{4}Zn{\cdot}2H_{2}O{\cdot}0.2\;mol$) and lithium hydroxide ($LiOH{\cdot}H_{2}O{\cdot}0.14\;mol$) in the ethanol were added to the solution containing a dispersing agent, hydroxypropyl cellulose (HPC). The nanosize and physical shape of the synthesized ZnO particles were determined by HPC acting as the dispersing agent. Nanosized ZnO particles were also obtained by a precipitation method based on zinc-2-ethylhexagonate. The precipitates were characterized by DLS, XRD, FE-SEM, and UV-vis. As the results, the ZnO colloids tend to self-assemble into a well-ordered hexagonal close-packed structure. The ZnO nanoparticles have an average diameter of nearly 40 nm with a narrow size distribution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.4
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• pp.117-124
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• 2024

Zinc oxide nanoparticles were synthesized using the polyol method with ethylene glycol containing hydroxyl groups (-OH). It was confirmed that the zinc compounds prepared by the polyol method were a mixture of zinc carbonate hydroxide (Zn₅(OH)₆(CO₃)₂) and zinc oxide (ZnO) crystalline structures. Calcination at 400℃, 600℃ and 800℃ was performed to examine the effects of calcination temperature on the particle size, morphology and crystallinity of zinc oxide. ZnO powders of calcination at 800 ℃ was evaluated to particle size analysis from ethylene glycol containing precursor solution compared with distilled water based solution. The zinc oxide particles obtained from the former had a particle size of approximately 404 ± 51 nm, whereas those from the latter exhibited a more uniform nanoparticles morphology with a particle size of approximately 109 ± 29 nm. This demonstrates that the addition of ethylene glycol can control the influence of water molecules, enabling the direct synthesis of zinc oxide in the form of uniform nanoparticles.