• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.05a
• /
• pp.191-191
• /
• 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.

• Journal of the Korean Ceramic Society
• /
• v.28 no.3
• /
• pp.252-258
• /
• 1991

Spectral properties of europium activated intermediate compounds in the system R2O3-P2O5(R=La, Y, and Gd) are presented, including also phosphors with bismuth and vanadate sensitization. The sensitized phosphors are less efficient than unsensitized phosphors. (The ratio of oxygen to phosphorus effects the charge transfer band) Most phosphors have low efficiencies, but La3PO7 and Gd3PO7 hosts are possible for commercial luminescent materials.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.204-206
• /
• 2009

Luminescent films were prepared by infiltration of tris(dibenzoylmethane) mono(1, 10-phenanthroline) europium incorporated ormosil into colloidal $SiO_2$ photonic crystal templates. The PL intensity of the infiltrated film into the template was about 13 times higher than that of the plane film prepared without the template.

• Bulletin of the Korean Chemical Society
• /
• v.6 no.3
• /
• pp.164-168
• /
• 1985

The fluorescence emission of polystyrene-acrylic acid copolymers containing $Eu^{3+}$ in tetrahydrofuran solution was investigated by spectrofluorimetry. The excimer emission increased linearly with the polymer concentration up to approximately $5{\times}10^{-3}$M. Benzene and toluene collisionally quenched the excimer fluorescence and thier rate constants of quenching were determined. Quenching efficiencies decreased in the order: naphthalene > toluene > benzene. Analyses of Rayleigh scattering and europium emission showed no measurable structural changes observed under the experimental conditions.

• Journal of the Korean Applied Science and Technology
• /
• v.23 no.3
• /
• pp.207-214
• /
• 2006

$Y_{2-x}Gd_xO_3:Eu$, phosphors for plasma display panel(PDP), were prepared by Pechini method which use yttriun chloride, gadolinium chloride, and europium oxide as starting materials. This method is a different way to the synthesis of europium(Eu)-doped phosphors, and it consists of the formation of a polymeric resin obtained by polyesterification between metal chelate compounds and a polyfunctional alcohol. This needs lower temperature than solid-state synthetic method. The prepared $Y_{2-x}Gd_xO_3:Eu$ phosphor particles had spherical shape and coherence. The luminescence intensity of $Y_{2-x}Gd_xO_3:Eu$ phosphor particles increased according to the increase of gadolinium(Gd) content(to 0.8mol%), and $Y_{1.2}Gd_{0.8}O_3:Eu$ phosphors had the highest luminescence intensity under vacuum ultra violet(VUV) excitation. The optimum concentration of Eu in the phosphor and optimum calcination temperature was 3wt% and $1100^{\circ}C$. The prepared phosphors were consist of particle, and its size was between 100nm and 150nm. Among the different polyfunctional alcohols, diethylene glycol(DEG) improved the luminescence intensities of phosphors more than other additives. The Pechini method proved that it is demonstrated to be suitable for the synthesis of phosphors used in PDP.

• Journal of the Korean Chemical Society
• /
• v.40 no.1
• /
• pp.65-71
• /
• 1996

The chemical behaviour of the Eu(Ⅲ) complexes with organic ligands(tris[3-(trifluoromethylhydroxymethylene-camphorato)]) and tris[3-heptafluoropropylhydroxymethylene-camphorato)] has been investigated by the UV/vis-spectrophotometric, magnetic, and electrochemcial methods. The two or three energy absorption bands are observed by the spectra of these complexes. The magnitude of crystal field splitting energy, the spin pair energy and strength were obtained from the spectra of the complexes. These complexes are found to be delocalization, low-spin state, and strong bonding strenth of electron configuration. The magnetic dipolemoment are found to be diamagnetic. The redox reaction processes of complexes were investigated by cyclic voltammetry in aprotic solvent. The redox reaction processes of complexes are turned out to be single or double reaction with respect to one electron diffusion current.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.12 no.3
• /
• pp.149-156
• /
• 2002

Europium-activated $Ga_2O_3$ phosphor powders were prepared by homogeneous precipitation method. The resulting powders were characterized by means of TG/DTA, XRD, FT-IR and SEM, Two kinds of powders formed were the crystalline GaOOH and the amorphous-like $\gamma$-$Ga_2O_3$ phases. When the urea concentration was below 0,5 M, rod-like micrometer-sized GaOOH powders were formed. They were transformed via $\alpha$-$Ga_2O_3$ to $\beta$-$Ga_2O_3$ phases under heat treatment. On the other hand, the nanometer-sized $\gamma$-$Ga_2O_3$ powders were formed with urea concentrations higher than 1.0 M, and they were directly changed into $\beta$-$Ga_2O_3$.Photoluminescence (PL) spectra were observed at room temperature, and PL intensities of nanometer-sized $Ga_2O_3$ : $Eu^{3+}$ powders around 610 nm were higher than those of micrometer-sized ones.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.447-452
• /
• 2003

We had clarified the reactions of the rare earth oxides($RE_2O_3$) with lithium oxide produced in lithium reduction process of oxide fuels. Oxides of scandium, yttrium, praseodymium, neodymium, samarium, europium, gadolinium, ytterbium and lutetium reacted with lithium oxide in the higher concentration than the respective certain critical concentration of lithium oxide and formed complex oxides($LiREO_2$). The critical lithium oxide concentrations for the formation of complex oxides of scandium, yttrium, praseodymium, neodymium, samarium, europium, gadolinium, ytterbium and lutetium oxide were respectively 0.1 wt%, 1.9 wt%, 5.3 wt%, 5.0 wt%, 3.0 wt%, 3.9 wt% 2.9 wt%, 2.6 wt% and 0.3 wt%. Cerium and lanthanum oxide did not react with lithium oxide. These complex oxides obtained from experiments have limited solubility in lithium chloride at $650^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.529-532
• /
• 1999

본 연구에서는 유기 전기 발광 소자에서 녹색 발광층으로 사용되는 terbium(Tb) complexes와 europium(Eu) complex, 정공 수송층으로 사용되는 TPD (N, N\`-diphenyl-N,\`(3-methylphenyl)-1, 1\`biphenyl-4, 4\`-diamine), 그리고 전자 수송층으로 사용되는 Alq$_{3}$ (trois(8-hydroxyquinolino)aluminum), Bebq$_2$들의 Uv/Vis. 홉광도와 PL 스펙 트럼과 같은 광학적 특성을 조사하였으며 또한 이러한 물질들을 이용하여 다양한 종류의 유기 전기 발광 소자를 제작하고 제작된 소자들의 전류밀도-전압-조도 등의 전기 . 광학적 특성을 조사하였으며, 그 결과 다 음과 같은 결곤을 얻을 수 있었다. 다양한 ligand를 갖는 Tb complex들의 경우에도 EL 스펙트럼의 파장대 (wavelength)는 546nm~548nm의 녹색 발광을 하는 것을 알 수 있었고, 제작된 소자 중에서 Tb(ACAC)$_3$(Phen) 을 발광충으로 하고, TPD, 그리고 Bebq$_2$를 각각 정공 수송층, 전자 수송 층으로 한 소자가 가장 낮은 구동 전압을 갖는다는 것을 확인하였으며 logJ-logV 특성에서도 모든 전계 구간에서 이러한 구조의 소자가 가장 높은 전류밀도를 나타냈으며 저 전계 구간에서 전류밀도 타이가 가장 컸다. 소자의 전류밀도와 휘도의 관계에 있어서는 제작된 네 종류의 소자 중 Tb(ACAC)3(Cl-Phen)를 발광층으로 하고 TPD, 그리고 Bebq2를 각각 정공 수송층, 전자 수송 층으로 한 소자가 가장 휘도가 우수한 것을 알 수 있었다. 또한 red (europium complex), green (terbium complex), 그리고 blue (TPD) 색깔을 나타내는 유기 재료를 사용하여 한 소자에서 백색 소자를 제작하여 cyclic voltametric방법을 이용하여 각 유기 물질들의 에너지 준위를 조사하여, 각각의 소자들을 에너지 밴드 다이어그램(energy band diagram)으로 자세히 설명하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1087-1090
• /
• 2004

Samples of yttrium oxide doped with trivalent europium have been prepared by ceramic techniques, under different synthesis conditions; barium chloride ($BaCl_2$) and sodium tetraborate ($Na_2B_4O_7$) were tested as flux. The improvement of luminescence properties in dependence on substitution of $Eu^{3+}$ for $Y^{3+}$ in the host lattice, under electron and UV excitations is demonstrated The obtained results are discussed with respect to the employed processing method.