• 대한화학회지
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• 제55권6호
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• pp.932-935
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• 2011

Using tetrabutyl titanate as precursor, $Eu^{3+}$ doped $TiO_2$ nano-powder was prepared by sol-gel method, the nature of luminescence of nano-powder was studied. The interaction of chlorpyrifos with $Eu^{3+}$ doped $TiO_2$ was studied by absorption and fluorescence spectroscopy. The results indicated the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was quenched by chlorpyrifos and the quenching rate constant ($k_q$) was $1.24{\times}10^{11}\;L/mol{\cdot}s$ according to the Stern-Volmer equation. The dynamics of photoinduced electron transfer from chlorpyrifos to conduction band of $TiO_2$ nanoparticle was observed and the mechanism of electron transfer had been confirmed by the calculation of free energy change (${\Delta}G_{et}$) by applying Rehm-Weller equation as well as energy level diagram. A new rapid method for detection of chlorpyrifos was established according to the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was proportional to chlorpyrifos concentration. The range of detection was $5.0{\times}10^{-10}-2.5{\times}10^{-7}mol/L$ and the election limit ($3{\sigma}$) was $3.2{\times}10^{-11}$ mol/L.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.155-158
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• 2002

Eu-doped lead zirconium titanate $Pb_{1.1}(Zr_{0.3}Ti_{0.7})O_{3}$ thin films on the Pt/Ti/$SiO_2$/Si substrates prepared by a metalorganic decomposition (MOD) method. The effect on the structural and electrical properties of the films measured according to Eu content. Eu-doping altered significantly the dielectric and ferroelectric properties. The remanent polarization and coercive field decreased with increasing the concentration of Eu content. The dielectric constant and dielectric loss of the film decreased with increasing Eu contents. The 3 mol% of Eu-doped PZT thin film showed large remanent polarization and the fatigue characteristic of the film did not change up to $10^9$ switching cycles.

• 한국전기전자재료학회논문지
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• 제20권3호
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• pp.223-227
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• 2007

The effect of Eu contents on the ferroelectric properties of $Bi_{4-x}Eu_xTi_3 O_{12}$ (BET) thin films has been investigated. Bismuth Europium titanate thin films with a Eu contents were prepared on the $Pt/Ti/SiO_2/Si$ substrate by metal-organic decomposition technique. The structure and the morphology of the films were analyzed using X-ray diffraction (XRD) and field emission scanning microscopy (FE-SEM), respectively. From the XRD analysis, it was found that BET thin films have polycrystalline structure, and the layered-perovskite phase is obtained when the Eu contents exceeds 0.2 (x > 0.2). Also, the ferroelectric characteristics of the BET thin films were found to be dependent on the Eu content. Particularly, the BET films doped with x = 0.75 show better ferroelectric properties (remanent polarization 2Pr = 60.99 C/$cm^2$ and only a little polarization fatigue up to $3.5{\times}10^9$ bipolar switching cycling) than those doped with other Eu contents.

• 한국전기전자재료학회논문지
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• 제16권7호
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• pp.611-615
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• 2003

Eu-doped lead zirconate titanate(Pb$\sub$1.1/(Zr$\sub$0.6/Ti$\sub$0.4/)O$_3$; PZT) thin films on the Pt/Ti/SiO$_2$/Si substrates prepared by a sol-gel method. The effect on structural and electrical properties of PZT thin films measured according to the Eu content. Eu-doping altered significantly dielectric and ferroelectric properties. The remanent polarization and the coercive field decreased with the increasing Eu content. The dielectric constant and the dielectric loss of PZT thin films decreased with the increasing Eu content. The 0.5 mol% of Eu-doped PZT thin film showed improved fatigue characteristic comparing to the undoped PZT thin film.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.483-484
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• 2006

$Eu^{3+}$와 $Pr^{3+}$이 첨가된 $SrTiO_3$형광체를 고상반응법으로 제조하였다. $SrTiO_3:Pr$형광체는 $^3P_J(J=0,1,2){\rightarrow}^3H_4$에 의한 490nm 부근의 녹색발광과 $^1D_2{\rightarrow}^3H_4$에 의한 618nm 의 적색발광이 동시에 나타났다. $SrTiO_3:Eu$형광체는 $SrTiO_3:Pr$형광체와 달리 $^5D_0{\rightarrow}^7F_1$에 의한 583nm와 $^5D_0{\rightarrow}^7F_2$에 의한 610nm의 적색발광만 각각 관찰되었다. $SrTiO_3$의 모체에서 $Eu^{3+}$는 inversion sysmmetry를 가짐으로써 610nm의 electric dipole transition 보다는 583nm의 magnetic dipole transition이 강하게 일어났다.

• 통합자연과학논문집
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• 제1권2호
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• pp.84-88
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• 2008

The formation and thermal properties of the $BaO_2$ and $TiO_2$ mixtures were prepared by mechanical alloying method was investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and thermogravimetric/differential thermal analysis (TG/DTA). The rotating speed of 750 rpm shows more effects on the formation of $BaTiO_3$ single phase. The internal strain calculated using Williamson-Hall method was $4.27{\times}10^{-3}$ for the mixture milled for 300 min, the crystallite size was calculated using the Scherrer method decreased with milling time. The $BaTiO_3$ crystal improved crystallinity was formed by thermal annealing at a temperature of $600^{\circ}C$ for 1 h for the mixture milled for 300 min.

• 한국결정성장학회지
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• 제30권6호
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• pp.232-236
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• 2020

본 연구에서는 광 발광특성이 우수하여 각종 광장치에 사용되고 있는 CaF2-Al2O3-B2O3-TiO2(CABT) 계 유리의 열처리 조건 및 결정상 생성에 따른 광학적 특성을 연구하였다. CAB 유리의 핵형성 및 결정성장을 제어하기 위해 핵형성제 TiO2를 첨가하고, 발광 특성을 향상시키기 위해 희토류 이온 Eu2O3를 첨가하였다. 열처리 조건에 따른 결정 성장 특성을 확인하기 위해 DTA 분석을 수행하였으며, 이에 따른 나노 크기 결정상 변화에 대한 XRD 및 SEM 분석을 수행하였다. 분석 결과 100 nm 크기의 결정생성은 발광강도를 향상시키지만 그 이상의 큰 결정 입자생성은 오히려 발광 특성을 저하시켰다.

• 한국전기전자재료학회논문지
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• 제32권3호
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• pp.229-233
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• 2019

Pure $BiFeO_3$ (BFO) and (Eu, V) co-doped $Bi_{0.9}Eu_{0.1}Fe_{0.975}V_{0.025}O_{3+{\delta}}$ (BEFVO) thin films were deposited on $Pt(111)/Ti/SiO_2/Si(100)$ substrates by chemical solution deposition. The effects of co-doping were observed by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy (SEM). The electrical properties of the BEFVO thin film were improved as compared to those of the pure BFO thin film. The remnant polarization ($2P_r$) of the BEFVO thin film was approximately $26{\mu}C/cm^2$ at a maximum electric field of 1,190 kV/cm with a frequency of 1 kHz. The leakage current density of the co-doped BEFVO thin film ($4.81{\times}10^{-5}A/cm^2$ at 100 kV/cm) was two orders of magnitude lower than of that of the pure BFO thin film.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.323-328
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• 2004

Down-conversion of Eu$^{3+}$ doped LiGdF$_4$ (LGF) for increasing the cell efficiency on dye-sensitized Ti $O_2$ solar cells has been studied. The dye sensitized solar cell (DSC) consisting of mesoporous Ti $O_2$ electrode deposited on transparent substrate, an electrolyte containing I$^{[-10]}$ /I$_3$$^{[-10]}$ redox couple, and Pt counter electrode is a promising alternative to the inorganic solar cell. The structure of DSC is basically a sandwich type, viz., FTO glass/Ru-red dye-absorbed Ti $O_2$/iodine electrolyte/sputtered Pt/FTO glass. The cell without down converter had open circuit potential of approximately 0.66 Volt, the short circuit photocurrent density of 1.632 mA/$\textrm{cm}^2$, and fill factor of about 50 ％ at the excitation wavelength of 550 nm. In addition, 5.6 mW/$\textrm{cm}^2$ incident light intensity beam was used as a light source. From this result, the calculated monochromatic efficiency at the wavelength of 550 nm of this cell was about 9.62 ％. The incident photon to current conversion efficiency (IPCE) of N3 used as a dye in this work is about 80 ％ at around 590 nm and 610 nm, which is the emission spectrum of Eu$^{3+}$ doped LGF, results in efficiency increasing of DSC.C.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.191-191
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• 2009

최근 많은 환경오염물질을 제거하기 위한 방법으로 광촉매를 이용한 기술들이 다양하게 활용되고 있다. 본 연구에서는 높은 비표면적을 갖는 관촉매를 제조하기 위해, 전기화학적인 방법인 양극 산화법을 사용하여 기지 Ti 금속 표면에 pore 형태의 광촉매용 $TiO_2$를 제조하고, 염료분해 반응을 통해 광촉매의 효율을 조사하였다. 또한 염료분해 효율을 높이기 위해 $Eu(NO_3)_3$를 첨가하여 염료분해 반응에 미치는 영향에 대해 조사하였다.