• Title/Summary/Keyword: $TiO_2-V_2O_5$ sol

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Synthesis of Nanocrystalline TiO2 by Sol-Gel Combustion Hybrid Method and Its Application to Dye Solar Cells

  • Han, Chi-Hwan;Lee, Hak-Soo;Han, Sang-Do
    • 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 ${^{\circ}C}$.

Low Temperature Sintering Process of Sol-gel Derived Ferroelectric Sr0.9Bi2.1Ta1.8Nb0.2O9 Thin films (Sol-gel 법으로 제조된 강유전체 Sr0.9Bi2.1Ta1.8Nb0.2O9 박막의 저온결정화 공정)

  • 김영준;김병호
    • Journal of the Korean Ceramic Society
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    • v.40 no.3
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    • pp.279-285
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    • 2003
  • Ferroelectric S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$ thin films with 200 nm thicknesses were deposited on Pt/Ti $O_2$/ $SiO_2$/Si Substrates by a sol-gel method. In these experiments, Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$ and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. After UV-irradiation and RTA processes, the remanent polarization value (2 $P_{r}$) of SBTN thin films with annealed at $650^{\circ}C$ was 8.49 and 11.94 $\mu$C/$\textrm{cm}^2$ at 3 V and 5 V, respectively.

Optical and dielectric Properties of $TiO_2$ hybrid thin films by dry sol-gel processing (Dry Sol-Gel법에 의한 $TiO_2$ hybrid 박막의 광학특성 및 유전특성에 관한 연구)

  • 정재훈;조종래;손세모;정수태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.315-318
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    • 2001
  • The optical and dielectric properties of TiO$_2$ thin films prepared with mixtures of Epoxy, bits-(4, 4'-p-toluenesulfonylacidic isoproplylidene)-cyclohexadiol and UVI 6990 in dry sol-gel process were investigated. The absorption peak of the films was showed at 360nm. Photocurrent of the thin films doped with 50 wt% of TiO$_2$was higher than that of nondoped thin films. Energy gap was lowered from 3.6 to 3.3 eV with increasing amount of TiO$_2$. Relative dielectric constants of samples were 1.5 to 3 and showed a characteristics of lower dielectric materials.

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A Study on Electrical Properties of Sol-gel Derived Bi3.25La0.75Ti3O12 Thin Films by Rapid Thermal Annealing (Sol-gel법으로 제조한 강유전성 Bi3.25La0.75Ti3O12박막의 급속열처리에 따른 전기적 특성에 관한 연구)

  • 이인재;김병호
    • 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.

A Study on the Characteristics of Semiconductor Oxides with V2O5 (V2O5가 첨가된 반도체 산화물의 특성개선연구)

  • Lee, Don-Kyu
    • Journal of IKEEE
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    • v.22 no.4
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    • pp.965-969
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    • 2018
  • In the dye-sensitized solar cell, the semiconductor oxide plays an important role in the generation and transport of electrons, and thus extensive research on this has been continuously carried out. In this study, the characteristics of dye-sensitized solar cell are studied by fabricating semiconductor oxide doped with $V_2O_5$. The $TiO_2$ paste with $V_2O_5$ is prepared by the screen printing method of the sol - gel process and the surface and electrical properties are measured. The addition of $V_2O_5$ increased grain size and improved the open circuit voltage, short circuit current, charge factor and conversion efficiency of the dye sensitized solar cell.

Preparation of Nano Titania Sols and Thin Films added with Transition Metal Elements (전이금속원소들이 첨가된 나노 티타니아 졸 및 코팅막 제조)

  • Lee K.;Lee N. H.;Shin S. H.;Lee H. G.;Kim S. J.
    • Korean Journal of Materials Research
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    • v.14 no.9
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    • pp.634-641
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    • 2004
  • The photocatalytic performance of $TiO_2$ thin films coated on porous alumina balls using various aqueous $TiOCl_2$ solutions as starting precursors, to which 1.0 $mol\%$ transition metal ($Ni^{2+},\;Cr^{3+},\;Fe^{3+},\;Nb^{3+},\;and\;V^{5+}$) chlorides had been already added, has been investigated, together with characterizations for $TiO_2$ sols synthesized simultaneously in the same autoclave through hydrothermal method. The synthesized $TiO_2$ sols were all formed with an anatase phase, and their particle size was between several nm and 30 nm showing ${\zeta}-potential$ of $-25{\sim}-35$ mV, being maintained stable for over 6 months. However, the $TiO_2$ sol added with Cr had a much lower value of -potential and larger particle sizes. The coated $TiO_2$ thin films had almost the same shape and size as those of the sol. The pure $TiO_2$ sol showed the highest optical absorption in the ultraviolet light region, and other $TiO_2$ sols containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ showed higher optical absorption than pure sol in the visible light region. According to the experiments for removal of a gas-phase benzene, the pure $TiO_2$ film showed the highest photo dissociation rate in the ultraviolet light region, but in artificial sunlight the photo dissociation rate of $TiO_2$ coated films containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ was measured higher together with the increase of optical absorption by doping.

Electrical Properties of $Al_2O_3/Si$ Ferroelectric Thin Films on $(Bi,La)Ti_3O_{12}$ Substrates by Sol-Gel Method (졸-겔법에 의해 $Al_2O_3/Si$ 기판위에 형성한 $(Bi,La)Ti_3O_{12}$강유전체 박막의 전기적 특성)

  • 황선환;장호정
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.11a
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    • pp.69-72
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    • 2002
  • B $i_{3.3}$L $a_{0.7}$ $Ti_3$ $O_{12}$(BLT) 강유전체 박막을 $Al_2$ $O_3$/Si 기판위에 졸-겔(sol-gel)법으로 스핀 코팅하여 Metal-Ferroelectric-Insulator-Silicon (MFIS) 구조를 형성하였다. 박막의 결정화를 위해 as-coated 박막을 산소분위기에서 $650^{\circ}C$$700^{\circ}C$에서 30분 동안 후속열처리를 실시하였다. BLT 박막의 열처리 온도를 $650^{\circ}C$에서 $700^{\circ}C$로 증가시킴에 따라서 c축으로 우선 배향되는 경향을 보였으며, FWHM 값이 감소하여 결정성이 향상됨을 확인할 수 있었다. $700^{\circ}C$에서 열처리된 BLT 박막의 memory window는 약 2.5V (인가전압 5V)를 나타내었으며, 누설전류는 약 1.5x$10^{-7}$ A/$\textrm{cm}^2$를 나타내었다.다.다.

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optimization and synthesis of $TiO_2$ for for the high efficiency DSSC (고효율 염료감응 태양전지를 위한 $TiO_2$의 합성 및 최적화)

  • Park, A-Reum;Ki, Hyun-Chul;Jin, En Mei;Gu, Hal-Bon
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.56.2-56.2
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    • 2011
  • 고효율 염료감응 태양전지를 제작하기 위해 Sol-gel법을 사용하여 $TiO_2$ 분말을 제조하였다. 제조 과정 중 다양한 양의 nitric acid를 첨가하여 pH를 조절하였다. Sol-gel법을 위한 출발 물질로 titanium (IV) isopropoxide(TTIP)와 DI water를 사용하였으며 nitric acid은 0, 0.05, 0.1, 0.15의 몰비(nitric acid/TTIP)로 첨가하였다. 첨가한 결과 pH는 $22^{\circ}C$에서 각각 5.52, 2.26, 1.68, 1.38이었다. 얻어진 $TiO_2$ 콜로이드 용액은 결정성 있는 분말로 제조 후 $5{\times}5[mm^2]$ 크기의 염료감응 태양전지를 제작하는데 사용 되였다. $TiO_2$의 결정구조 및 형태는 cell의 XRD와 FE-SEM으로 분석되었고 전기화학적 특성을 분석하기 위해 irradiation of AM 1.5 ($100mW/cm^2$) simulatedsunlight에서 I-V 곡선을 측정하였다. 측정 결과 몰비(nitric acid/TTIP) 0.05, pH가 2.26일 때 가장 우수한 효율 특성을 보였다.

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Synthesis of TiO2 by Sol-gel Method and Electrochemical Properties of DSSCs with Controlling pH (졸겔법을 통한 TiO2 합성 및 pH에 따른 DSSC의 전기화학적 특성)

  • Park, A-Reum;Kim, Seon-Hoon;Kim, Doo-Gun;Gu, Hal-Bon;Ki, Hyun-Chul
    • 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.

Microstructure and electrical properties of PZT thin films by sonicated sol in an ultrasonic bath (초음파 처리된 sol로 제조된 PZT 박막의 미세구조 및 전기적 특성)

  • 김종국;박병옥
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.1
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    • pp.101-106
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    • 1999
  • Pb$(Zr_{0.5},Ti_{0.5})O_3$ thin films were prepared on $Pt/Ti/SiO_2/Si$substrates by spin-coating. The sol was sonicated in an ultrasonic bath to promoto homogenization and the results were compared with untreated case. In the case of PZT thin films prepared from sonicated sol, only perovskite phase was obtained at $550^{\circ}C$ and "rosette" structures in the films disappeared. Dieletric constants (10kHz), remnant polarization, and coercive field of the films prepared from untreated and sonicated sol were 335 and 443, 12.3 and17.7$\mu$C/$\textrm{cm}^2$, 168.4 and 153.5 kV/cm. Electrical properties were improved by introduction of the sonication processon process

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