• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1579-1582
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• 2013

• 한국결정성장학회지
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• 제31권5호
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• pp.197-202
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• 2021

Z형 육방정 페라이트인 Ba₃Co₂Fe₂₄O₄₁(Ba₃Z)와 Ba_1.5La_1.5Co₂Fe₂₄O₄₁(Ba_1.5La_1.5Z) 분말을 1차 하소 후 용융염 합성법을 통해 합성하였다. Ba₃Z의 경우, 1000℃에서 하소한 결과 M형 육방정 페라이트와 Y형 육방정 페라이트가 합성되었으며, 이후 1150℃와 1200℃에서 소결했을 때 Z형 육방정 페라이트를 얻을 수 있었다. 하지만 Ba_1.5La_1.5Z의 경우 1000℃에서 하소하였을 때 M형 육방정 페라이트와 CoFe₂O₄(Spinel 상) 그리고 LaFeO₃으로 합성되었으며, Z형 육방정 페라이트는 용융염 합성 과정에서 합성되지 않았다. 또한 입자 형상의 종횡비는 용융염 합성 시 소결온도가 증가함에 따라 감소하는 경향을 보였다. 따라서 높은 종횡비를 갖는 단상의 Ba_1.5La_1.5Z를 합성하기 위해서는 용융염 합성 전 1차 하소 온도가 Spinel 상이 형성되는 온도보다 낮아야 될 것으로 판단된다.

• 한국세라믹학회지
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• 제54권4호
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• pp.278-284
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• 2017

In this work, Ta-substituted $Li_7La_3Zr_{2-x}O_{12}$ (LLZTO) powder and pellets with garnet cubic structure were fabricated and characterized by modified and optimized sol-gel synthesis. Ta-substituted LLZO powder with the smallest grain size and pure cubic structure with little pyrochlore phase was obtained by synthesis method in which Li and La sources in propanol solvent were mixed together with Zr and Ta sources in 2-methoxy ethanol. The LLZTO pellets made with the prepared powder showed cubic garnet structure for all conditions when the amount of Li addition was varied from 6.2 to 7.4 mol. All the X-ray peaks of the pyrochlore phase disappeared when the Li addition was increased above 7.0 mol. When the final sintering temperature was varied, the LLZTO pellet had a pyrochlore-mixed cubic phase above $1000^{\circ}C$. However, the surface morphology became much denser when the final sintering temperature was increased. The sol-gel-driven LLZTO pellet with a sintering temperature of $1100^{\circ}C$ showed a lithium ionic conductivity of 0.21 mS/cm when Au was adopted as electrode material for the blocking capacitor. The results of this study suggest that modified sol-gel synthesis is the optimum method to obtain cubic phase of LLZTO powder for highly dense and conductive solid electrolyte ceramics.

• 한국지구과학회지
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• 제23권1호
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• pp.52-58
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• 2002

A colorless and transparent zirconium oxide ($Zr_{0.73}Y_{0.27}O_{1.87}$) crystal has been synthesized by the Bridgman-Stockbager method. The gem-quality material is produced by adding 20${\sim}$25 wt.% $Y_2O_3$ (stabilizer) and 0.04 wt.% $Nd_2O_3$ (decolorising agent) to the $ZrO_2$ powder. It shows a vitreous luster with a slight oily appearance. Under a polarizing microscope, it shows isotropic nature with no appreciable anisotropism. Mohs hardness value and specific gravity is measured to be 8${\sim}$$8{\frac{1}{2}}$ and 5.85, respectively. Under ultraviolet light it shows a faint white glow. The crystal structure of yttria-stabilized zirconia with 0.27 at.% Y has been re-investigated, using single crystal X-ray diffraction, and confirmed to be a cubic symmetry, space group $Fm{\overline{3}}m$ ($O^5_h$) with a=5.1552(5) ${{\AA}}$, V=136.99(5) ${{\AA}}^3$, Z=4. The stabilizer atoms randomly occupy the zirconium sites and there are displacements of oxygen atoms with amplitudes of ${\Delta}/a{\sim}$0.033 and 0.11 along <110> and <111> from the ideal positions of the fluorite structure, respectively.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1617-1620
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• 2008

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2467-2470
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• 2009

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.202-207
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• 2024

This study examines a manufacturing process for the photoelectrode material of dye-sensitized solar cell (DSSC) intending to increase efficiency through the surface plasmon resonance phenomenon of nanoparticles with a composite structure made of Ag and TiO₂. This invention involves the use of Ag and TiO₂ nanoparticles in the solar cell. These nanoparticles cause surface plasmon resonance, which amplifies and scatters incident solar energy, enhancing the dye's rate of light absorption. It also makes it possible to absorb energy in wavelength ranges that were previously difficult to do, which increases efficiency. Centrifugal separation and heat synthesis are used to create the composite metal structures, and certain combinations are used to decide the particle morphologies. To increase the efficiency of organic solar cells and DSSC, the Ag/TiO₂ composite structure is therefore quite likely to be used.

• 대한화학회지
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• 제60권5호
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• pp.321-326
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• 2016

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.497-499
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• 2010

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2773-2776
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• 2009