• Current Photovoltaic Research
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• v.3 no.3
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• pp.97-100
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• 2015

The kesterite $Cu_2ZnSnSe_4$ (CZTSe) thin film solar cells were synthesized by selenization of sputtered Cu/Sn/Zn metallic precursors on Mo coated soda lime glass substrate in Ar atmosphere. Cu/Sn/Zn metallic precursors were deposited by DC magnetron sputtering process with 30 W power at room temperature. As-deposited metallic precursors were placed in a graphite box with Se pellets and selenized using rapid thermal processing furnace at various temperature ($480^{\circ}C{\sim}560^{\circ}C$) without using a toxic $H_2Se$ gas. Effects of Selenization temperature on the morphological, crystallinity, electrical properties and cell efficiency were investigated by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD), J-V measurement system and solar simulator. Further details about effects of selenization temperature on CZTSe thin films will be discussed.

• Elastomers and Composites
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• v.51 no.4
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• pp.286-300
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• 2016

$MoS_2$ precursors were synthesized by reacting thioacetamide ($C_2H_5NS$) with sodium molybdate dihydrate ($Na_2MoO_4{\cdot}2H_2O$) in aqueous HCl solution. $MoS_2$ nanoparticles were prepared from dried $MoS_2$ precursors by calcination in an electric furnace at $700^{\circ}C$ for 2 h under an inert argon atmosphere. $MoS_2-C_{60}$ nanocomposites were obtained by heating $MoS_2$ nanoparticles and fullerene ($C_{60}$) together in an electric furnace at $700^{\circ}C$ for 2 h. Their morphological and the structural properties were characterized by powder X-ray diffraction and scanning electron microscopy. The $MoS_2$ nanoparticles and $MoS_2-C_{60}$ nanocomposites were used as catalysts in the reductions of 2-, 3-, and 4-nitrophenol in the presence of sodium borohydride. The photocatalytic activities of the $MoS_2$ nanoparticles and $MoS_2-C_{60}$ nanocomposites were evaluated in the degradation of organic dyes (brilliant green, methylene blue, methyl orange, and rhodamine B) under ultraviolet light (254 nm).

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.217-218
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• 2002

대기환경 중의 오존은 유기용제의 사용 및 차량에서 배출되는 휘발성 방향족 화합물과 오존전구물질(ozone precursors)이 대기 중에서 광화학반응을 통하여 만들어지는 것으로 알려져 있다. 오존은 호흡기계통의 기관지염 및 감기, 현기증과 같은 인체의 건강상에도 매우 나쁜 영향을 초래하고 있어 이에 대한 모니터링이 중요한 과제로 대두되고 있다. 본 연구에서는 고가의 장비가 소요되는 기존의 분석법인 저온농축법과 흡착법을 이용하는 대신에 고체상 미량추출방법 (Solid-Phase Microextraction, 이하 SPME)을 이용하여 GC/MS로 대기 중 오존 VOC를 ppt 수준까지 빠르고 신속하게 분석하는 방법을 확립하였다. (중략)

• Journal of the Korean Ceramic Society
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• v.29 no.12
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• pp.942-948
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• 1992

Ultrafine iron oxide powder, {{{{ gamma }}-Fe2O3 and $\alpha$-Fe2O3, were prepared by the thermal decomposition of organometallic compounds. The formation process of powder includes the thermal decomposition and oxidation of the organometallic precursors, Fe(N2H3COO)2(N2H4)2 (A) and N2H5Fe(N2H3COO)3.H2O (B). The organometallic precursors, A and B, were synthesized by the reaction of ferrous ion with hydrazinocarboxylic acid, and characterized by quantitative analysis and infrared spectroscopy. The mechanistic study for the thermal decomposition was performed by DAT-TG. The iron oxide powder was obtained by the heat treatment of the precursors at 20$0^{\circ}C$ and $600^{\circ}C$ for half an hour in air. The phases of the resulting product were proved {{{{ gamma }}-Fe2O3 and $\alpha$-Fe2O3 respectively. The particle shape was equiaxial and the particle size was less than 0.1 ${\mu}{\textrm}{m}$. Magnetic properties of the {{{{ gamma }}-Fe2O3 powder obtained from A and B was 234 Oe of coercivity, 64.26 emu/g of saturation magnetization, 23.59 emu/g of remanent magnetization and 24.1 Oe, 47.27 emu/g, 3.118 emu/g respectively. The value of $\alpha$-Fe2O3 powder was 1.494 Oe, 0.4862 emu/g, 0.1832 emu/g and 1,276 Oe, 0.4854 emu/g, 0.1856 emu/g respectively.

• Journal of the Korean Ceramic Society
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• v.43 no.7 s.290
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• pp.402-407
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• 2006

NiO/YSZ(70 wt%NiO) composite powders were prepared by ball-milling of 8YSZ and NiO precursors, dried and then followed by calcination. The approach was to combine acidic $Ni(NO_3)_2{\cdot}6H_2O$ and basic $2NiCO_3{\cdot}3Ni(OH)_2{\cdot}4H_2O$ via acid-base reaction as a mixed NiO precursor. Their effects were studied in the aspects of DSC, microstructure, porosity, and electrical conductivity. Ni/YSZ composite of 1N9C (1 mole NiO from the nitrate and 9 moles of NiO from the carbonate) was prepared by consolidation at $1400^{\circ}C$ for 3 h, and then followed by reduction at $1000^{\circ}C$ for 3 h under flowing of 6% $H_2/N_2$. It showed a homogeneous microstructure with ${\sim}20%$ porosity and 1880 S/cm at $1000^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1398-1402
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• 1998

• Bulletin of the Korean Chemical Society
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• v.16 no.12
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• pp.1180-1184
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• 1995

The precursors of Ba1-xSrxTiO3(x=0.0-0.3) were prepared by the rapid addition of aqueous solution of titanyl oxalate to the mixed aqueous solution of barium and strontium at room temperature. The optimum pH was theoretically calculated from the equilibrium constants and solubility products. The chemical formula of the precursors obtained corresponded to Ba1-xSrxTiO(C2O4)2·4H2O(x=0.0-0.3) as determined by thermal gravimetric analysis. The precursors were converted to stoichiometric Ba1-xSrxTiO3(x=0.0-0.3) with a particle size of 0.01-0.04 μm. As increasing the amount of strontium substituted to barium sites, the structure of crystal changed from the tetragonal phase to the cubic and the unit cell volume was decreased.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.506-510
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• 2004

There have been intensive studies concerning $[^{11}F]$choline ($[^{11}F]$methyldimethyl( ${\beta}$ -hydroxyethyl) ammonium) (1) which is known as a very effective tracer in imaging various human tumors localized in brain, lung, esophagus, rectum, prostate and urinary bladder using Positron Emission Tomography (PET) and there is increasing interest in $^{18}F$ labelled choline (2) and proved to be useful to visualize prostate cancer. We have prepared six $^{18}F$ labelled alkyl choline derivatives (3a-3c, 4a-4c) from ditosylated and dibrominated alkanes in moderate yields. The six alkyl tosylate or bromate ammonium salts have been synthesized as precursors. Radiofluorination was achieved by the treatment of precursors with $^{18}F$ - in the presence of Kryptofix-2.2.2.. The labeling yields varied ranging from 7 to 25%.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.653-656
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• 2009

3-Dimensionally ordered macroporous $LiMn_2O_4$ thin film was prepared by a sol-gel and dip coating method on Pt/Ti/$SiO_2$/Si substrate. An opal structure consisting of mono dispersed polystyrene beads (300 nm) was used as a template. After solution containing Mn and Li precursors was coated on the template-deposited substrate, the template and organic materials in the precursors was removed by calcination at 400 ${^{\circ}C}$. And then the 3-dimensional $LiMn_2O_4$ thin film with spinel structure was fabricated by heat treatment at 700 ${^{\circ}C}$. The structural and electrochemical property was investigated by XRD, SEM and charge-discharge cycler.

• Advances in Energy Research
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• v.2 no.2
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• pp.97-104
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• 2014

A co-spray deposition technique has been developed to bypass a fundamental limitation in the conventional spray deposition technique, i.e., the deposition of metal oxides from incompatible precursors in the starting solution. With this technique, ZnO films codoped with F and Al have been successfully synthesized, in which F is incompatible with Al. Two starting solutions were prepared and co-sprayed through two separate spray heads. One solution contained only the F precursor, $NH_4F$. The second solution contained the Zn and Al precursors, $Zn(O_2CCH_3)_2$ and $AlCl_3$. The deposition was carried out at $500^{\circ}C$ on soda-lime glass in air. A minimum sheet resistance, $55.4{\Omega}/{\square}$, was obtained for Al and F codoped ZnO films after vacuum annealing at $400^{\circ}C$, which was lower than singly-doped ZnO with either Al or F. The transmittance for the codoped ZnO samples was above 90% in the visible range. This co-spray deposition technique provides a simple and cost-effective way to synthesize metal oxides from incompatible precursors with improved properties for photovoltaic applications.