• Title/Summary/Keyword: sol-gel solution

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Preparation and ferroelectric properties of the $Pb(Zr_{0.52}Ti_{0.48})O_3$ thin film by Sol-Gel method (SoI-Gel법에 의한 $Pb(Zr_{0.52}Ti_{0.48})O_3$박막의 제조 및 강유전 특성)

  • 정장호;박인길;류기원;배선기;이영희
    • Electrical & Electronic Materials
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    • v.8 no.5
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    • pp.606-610
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    • 1995
  • In this study, Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ ceramic thin films were fabricated from an alkoxide-based by Sol-Gel method. Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ stock solution was made and spin-coated on the Pt/ $SiO_{2}$/Si substrate at 4000[rpm] for 30[sec.]. Coated specimens were chied at 400[.deg. C] for 10[min]. The coating process was repeated 6 times and then heat-treated at 500-800[.deg. C] and 1 hour. The final thickness of the thin films were about 4800[.angs.]. The ferroelectric perovskite phases precipitated under the sintering of 700[.deg. C] for 1 hour. Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ thin films sintered at 700[.deg. C] for 1 hour showed good dielectric and ferroelectric properties.

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Fabrication of YBa_2Cu_3O_{7-x}$ceramic using the Sol-Gel process (졸-겔 법으로 YBa_2Cu_3O_{7-x}$세라믹의 제조)

  • Kim, Hyun-Taek;Kang, Hyung-Boo;Kim, Bong-Heup
    • Proceedings of the KIEE Conference
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    • 1989.07a
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    • pp.299-301
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    • 1989
  • This study presents a method of preparing $YBa_2Cu_3O_{7-x}$ ceramic and chlorine doping in it for the purpose of Jc enhancement us ins sol-gel process.Tetramethylammonium-hydroxide and pottasium carbonate solution were added to the aqueous solution of Yttrium nitrate, Barium chloride and Copper nitrate for pH control as well as forming hydroxy-carbonate precipitation. Instead of Barium nitrate, Barium chloride was used for doping chloride impurities in the specimen. The resulted materal showed good high Tc-superconductivity after calcination. Tc and Jc value are 92 K and 120.8 $A/cm^2$ respectively.

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Influence of Compositions on Sol-Gel Derived Amorphous In-Ga-Zn Oxide Semiconductor Transistors

  • Kim, Dong-Jo;Koo, Chang-Young;Song, Keun-Kyu;Jeong, Young-Min;Moon, Joo-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1586-1589
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    • 2009
  • We investigated the influence of chemical compositions of gallium and indium cations on the performance of solgel derived amorphous gallium indium zinc oxide (a-GIZO) based thin-film transistors (TFTs). Systematical composition study allows us to understand the solutionprocessed a-GIZO TFTs. Understanding of the compositional influence can be utilized for tailoring the solution processed amorphous oxide TFTs for the specific applications.

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Preparation and Characterization of Spherical Silica-coated Ceria Nanoparticles by Sol-Gel Method

  • Ahn, Yang-Kyu;Jeoung, Hae-Chan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.96-96
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    • 2010
  • Monodispersed spherical silica-coated ceria nanoparticles were prepared through a sol-gel process using tetraethylorthosilicate (TEOS) and ceria fine particles. In this process, ceria fine particles were also prepared from cerium nitrate. The mean size of ceria particles was 300nm. Silica nanoparticles with narrow particle size distribution were prepared by controlled hydrolysis of TEOS solution. The silica sols were obtained by peptization, the process of redispersing a coagulated colloid, and were coated on ceria particles by the control of the weight ratio of silica/ceria and the pH of the mixture in aqueous solution. The morphologies of particles were characterized with scaning electron microscopy(SEM), transmission electron microscopy(TEM) and atomic force microscopy(AFM). The coating thickness of silica particles obtained by using this method was controlled in the range of 30 - 70nm.

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Synthesis of Lauric Acid Based Phase Change Materials Via Sol-gel Route (졸겔 법을 통한 라우르산 기반의 상변화 물질의 합성)

  • Ishak, Shafiq;Lee, Han Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.42-43
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    • 2020
  • Lauric acid (LA) which is also known as dodecanoic acid has been selected as the phase change material (PCM) owing to eco-friendly in nature. A systematic study has been conducted for encapsulation of LA (core) with silicon dioxide (SiO2) as shell material. Different core-shell ratio was chosen to microencapsulate the LA with 10 ml of tetraethyl orthosilicate (TEOS) as the precursor solution for the formation of SiO2. The synthesis of microencapsulated LA was carried out at 2.5 pH of precursor solution. The synthesized microencapsulated LA are characterized by Fourier transform infrared spectroscope (FT-IR) and X-Ray Diffraction (XRD) which confirmed the presence of SiO2 shell on the surface of LA.

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Growth and electrical properties of Pb(Zr, Ti)$O_3$ thin films by sol-gel method (솔-젤 법을 이용한 Pb(Zr, Ti)$O_3$ 박막의 성장 및 전기적 특성에 관한 연구)

  • 김봉주;전성진;이재찬;유지범
    • Journal of the Korean Vacuum Society
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    • v.8 no.4A
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    • pp.425-431
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    • 1999
  • $Pb(Zr_{0.52}, Ti_{0.48})O_3$ (PZT) thick films as an actuating material with conducting oxides, $(La_{0.5}Sr_{0.5}) CoO_3$ (LSCO), have been fabricated by sol-gel method for Optical Micro-Electro-Mechanical System (MEMS) devices, in which PZT/LSCO/SiO2 structures were used. In order to improve the adhesion to LSCO solution in order to enhance the wetting behavior of a water-based LSCO precursor solution and further to improve the adhesion between LSCO and $SiO_2$ layers. PZT films were made using 1-3 propanediol based precursor solution which has a high viscosity and a boiling point appropriate for thick film fabrication. In the precursor solution, Ti-propoxied and Zr-propoxied are partially substituted with acetylacetone to achieve the solution stability while maintaining reactivity. Crack free PZT films (0.8~1$\mu\textrm{m}$) have been successfully fabricated at crystallization temperatures above $700^{\circ}C$. Dielectric constants and dielectric losses of the PZT films were 900~1200and 2~5%, respectively. Piezoelectric constant $d_{33}$ of the PZT films constrained by a substrate were 200pm/V at 100kV/cm.

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The crystallization behaviours of cordierite gel derived from sil-gel method and glass prepared by the conventional melting method. (용융법과 졸겔법으로 제조된 Cordierite 계 유리와 겔의 결정화 거동)

  • Park, Won-Gyu
    • The Journal of Engineering Research
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    • v.1 no.1
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    • pp.15-22
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    • 1997
  • The crystallization behaviours of cordierite gel derived from sol-gel method and glass prepared from conventional melting method with or without $TiO_2$ as nucleants are compared. The densification temperature of gel is $810^{\circ}C$ and its chemical structure identified by IR analysis is same as that of glass melted by conventional method. The beginning crystallization temperature of gel is $965^{\circ}C$ lower than that of melted glass with 10wt% $TiO_2$, which is $978^{\circ}C$. The crystalline phases developed from gel during heat treatment are identified as spinel, $\beta$-quartz solid solution and $\alpha$-cordierite crystal and crystalline phases in case of glass are (Mg,Al)TiOn and $\beta$-quartz solid solution and $\alpha$-cordierite crystal, respectively. The crystallization in melted glass with nucleants occurs through bulk crystallization and in case of that without nucleants surface crystallization occurs, while the crystallization in gel is internal crystallization from interface between particles formed after densification.

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Phase Behavior of a PEO-PPO-PEO Triblock Copolymer in Aqueous Solutions: Two Gelation Mechanisms

  • Park, Moon-Jeong;Kookheon Char;Kim, Hong-Doo;Lee, Chang-Hee;Seong, Baek-Seok;Han, Young-Soo
    • Macromolecular Research
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    • v.10 no.6
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    • pp.325-331
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    • 2002
  • Phase behavior of a PEO-PPO-PEO (Pluronic P103) triblock copolymer in water is investigated using small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and rheology. Pluronic P103 shows apparent two gel states in different temperature regions. The first sol-to-gel transition at a lower temperature (i.e., the hard gel I state) turns out to be the hexagonal microphase as evidenced by the combined SANS and SAXS and the frequency dependence of both G′ and G" in rheology. In contrast to the hard gel I, the second sol-to-gel transition (i. e., the hard gel II state) at a higher temperature represents the block copolymer micelles in somewhat disordered state rather than the ordered state seen in the hard gel I. Moreover, turbidity change depending only on the temperature with four distinct regions is observed and the large aggregates with size larger than 5,000 nm are detected with DLS in the turbid solution region. Based upon the present study, two different gelation mechanisms for aqueous PEO-PPO-PEO triblock copolymer solutions are proposed.

Synthesis of Highly Concentrated ZnO Nanorod Sol by Sol-gel Method and their Applications for Inverted Organic Solar Cells

  • Kim, Solee;Kim, Young Chai;Oh, Seong-Geun
    • Korean Chemical Engineering Research
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    • v.53 no.3
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    • pp.350-356
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    • 2015
  • The effects of the zinc oxide (ZnO) preparing process on the performance of inverted organic photovoltaic cells (OPVs) were explored. The morphology and size of ZnO nanoparticles were controlled, leading to more efficient charge collection from device and higher electron mobility compared with nanospheres. Nanosized ZnO particles were synthesized by using zinc acetate dihydrate and potassium hydroxide in methanol. Also, water was added into the reaction medium to control the morphology of ZnO nanocrystals from spherical particles to rods, and $NH_4OH$ was used to prevent the gelation of dispersion. Solution-processed ZnO thin films were deposited onto the ITO/glass substrate by using spin coating process and then ZnO films were used as an electron transport layer in inverted organic photovoltaic cells. The analyses were carried out by using TEM, FE-SEM, AFM, DLS, UV-Vis spectroscopy, current density-voltage characteristics and solar simulator.