• Carbon letters
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• v.10 no.2
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• pp.123-130
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• 2009

Multi-elements doped $TiO_2$ was prepared as a new photocatalyst in order to decrease the band gap of $TiO_2$ by sol-gel process which can provide the large active sites of $TiO_2$. Multi-elements were doped by using a single precursor, tetraethylammonium tetrafluoroborate (TEATFB). By the benefit of large specific surface area of $TiO_2$ prepared by sol-gel process, catalysts showed initial fast removal of dye. The photoactivity showed that the doped catalysts significantly promote the light reactivity than undoped $TiO_2$. The commendable photoactivity of prepared catalysts is predominantly attributable to the doping of anions which may reduce the band gap.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.620-625
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• 2012

The sol-gel method has been widely used to synthesize the $TiO_2$ for dye sensitized solar cells and has advantages of easily fabrication process, controlling the $TiO_2$ phase and getting transparent thin-film composed of the $TiO_2$. In this paper, we synthesized the crystalline $TiO_2$ by sol-gel method controlled by the quantity ratio of Nitric acid and Ammonium hydroxide additives. The best efficiency result was obtained by 0.05 M Ammonium hydroxide and that results of Voc, Jsc, FF, and efficiency were 0.68 V, 3.28 mA/$cm_2$, 58.14 and 5.21%, respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.58.1-58.1
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• 2009

나노 임프린트 리소그래피 기술은 기존의 노광 장비를 이용하는 기존의 리소그래피 공정에 비해 저렴한 공정으로 대면적 패터닝이 가능한 차세대 리소그래피 기술이다. 나노 임프린트 리소그래피는 기존의 나노 리소그래피 기술과는 다르게 기능성 무기물 물질을 직접 패터닝 할 수 있는 기술이다. 본 연구에서는 $TiO_2$ 나노 패턴을 를 기존의 증착, 리소그래피, 식각 등의 공정을 거치지 않고, sol-gel법과 나노 임프린트 리소그래피를 이용하여 직접 전사하는 기술에 대해 연구 하였다. 본 연구에서는 Tetrabutylorthotitanate를 precusor로 하는 ethanol 기반의 $TiO_2$ sol을 제작하여 이용하였다. PDMS mold를 임프린팅용 몰드로 사용하였으며, 이러한 PDMS mold는 노광 기술과 반응성 이온 식각을 이용하여 제작된 master mold로 부터 복제되었다. 제작된 sol을 Si wafer에 spin coating하여 넓게 도포한 후, wafer위에 PDMS mold를 밀착 시킨다. 이후, 5 bar의 압력과 $200^{\circ}C$의 온도에서 나노 임프린트 리소그래피 공정을 진행하여 $TiO_2$ gel 패턴을 형성한다. gel 상태의 $TiO_2$ 패턴을 anealing 공정을 통해 다결정질 TiO2 나노 패턴으로 제작하였다. 제작된 패턴을 scanning electron microscope(SEM)를 이용하여 확인하고, XRD 및 EDX를 이용하여 분석하였다.

• Journal of the Korean Ceramic Society
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• v.33 no.10
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• pp.1147-1155
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• 1996

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.129.2-129.2
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• 2007

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.207-212
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• 2001

In this study, synthesis condition of $TiO_2$ thin films which have optimal dielectric characteristics using sol-gel method was determined. Thin films were fabricated using sol which have optimal characteristics and their permittivity was measured. In case of the amount of water for hydrolysis smaller than that for stoichiometry, sol formed clear sol which have normal chain structure. On the contrary, in case of the amount of water for hydrolysis larger than that for stoichiometry, sol formed suspended sol which have cluster structure. The permittivity of thin films increased exponentially around $^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1366-1370
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• 2001

Thin films of the SiO2-TiO2-PDMS composite material have been prepared by the sol-gel dip coating method. Acid catalyzed solutions of tetraethoxy silane (TEOS) and polydimethyl siloxane (PDMS) mixed with titanium isopropoxide Ti(OiPr) were used as precursors. The optical and structural properties of the organically modified 70SiO2-30TiO2 composite films have been investigated with Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Spectroscopy (UV-Vis), Differential Thermal Analysis (DTA) and prism coupling technique. The films coated on the soda-lime-silicate glass exhibit 450-750 nm thickness, 1.56-1.68 refractive index and 88-94% transmittance depending on the experimental parameters such as amount of PDMS, thermal treatment and heating rate. The optical loss of prepared composite film was measured to be about 0.34 dB/cm.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1189-1196
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• 2003

Ferroelectric B $i_{3.25}$L $a_{0.75}$ $Ti_3$ $O_{12}$ (BLT) solution was synthesized by sol-gel process. BLT thin films were deposited on Pt/Ti $O_2$/ $SiO_2$/Si substrates by spin-coating. In this experiments, Bi(TMHD)$_3$, La(III)2-Methoxyethoxide, and Ti(IV) i-propoxide were used as starting materials, which were dissolved in 2-Methoxyethanol. Rapid Thermal Annealing (RTA) was used to promote crystallization of BLT thin films. The thin films with RTA process were compared with those with non-RTA process on electrical properties. After RTA process, the remanent polarization value (2Pr) of BLT thin films annealed at 72$0^{\circ}C$ was 20.46 $\mu$C/$\textrm{cm}^2$ which was approximately 27% higher than that of non-RTA process at 5 V.

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1495-1498
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• 2008

$TiO_2$ nanopowders were synthesized by new sol-gel combustion hybrid method using acetylene black as a fuel. The dried gels exhibited autocatalytic combustion behaviour. $TiO_2$ nanopowders with an anatase structure and a narrow size distribution were obtained at 400-600 ${^{\circ}C}$. Their crystal structures were examined by powder Xray diffraction (XRD) and their morphology and crystal size were investigated by scanning electron microscopy (SEM). The crystal size of the nanopowders was found to be in the range of 15-20 nm. $TiO_2$ powders synthesized at 500 ${^{\circ}C}$ and 600 ${^{\circ}C}$ were applied to a dye solar cell. An efficiency of 5.2% for the conversion of solar energy to electricity ($J_{sc}$ = 11.79 mA/$cm^2$, $V_{oc}$ = 0.73 V, and FF = 0.58) was obtained for an AM 1.5 irradiation (100 mW/$cm^2$) using the $TiO_2$ nanopowder synthesized by the sol-gel combustion hybrid method at 500 ${^{\circ}C}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.9
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• pp.711-717
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• 1998

BST(70/30) and BST(50/50) thin films were prepared by Sol-Gel method and studied about the microstructural and dielectric properties with Pt and ITO bottom electrodes. The stock solution was synthesized and spin coated on the Pt/Ti$SiO_2$/Si and Indium Tin Oxide(ITO)/ glass substrate. the coated films were dries at 350$^{\circ}C$ for 10 minutes and annealed at $750^{\circ}C$ for 1 hour for the crystallization. The thin films coated on ITO substrate were crystallized easily and the packing density and roughness of surface were better that those of films coated on Pt substrates. In the BST(50/50) composition the structural properties were similar to the BST(70/30) composition and grain size were decreased with increasing the contents of Sr. The dielectric constant was higher in the BST(50/50) composition compared with the BST(70/30) composition. Using the ITO substrate, the dielectric constant was higher than the Pt substrate while the dielectric loss was showed a reverse trend. The dielectric constant with and increase of temperature was decreased slowly.