• Journal of the Korean institute of surface engineering
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• v.56 no.3
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• pp.201-207
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• 2023

Eu³⁺-doped SnO² (SnO²:Eu³⁺) phosphor thin films were grown on quartz substrates by radio-frequency magnetron sputtering. The deposition temperature was varied from 100 to 400 ℃. The X-ray diffraction patterns showed that all the thin films had two mixed phases of SnO₂ and Eu₂Sn₂O₇. The 880 nmthick SnO²:Eu³⁺ thin film grown at 100 ℃ exhibited numerous pebble-shaped particles. The excitation spectra of SnO²:Eu³⁺ thin films consisted of a strong and broad peak at 312 nm in the vicinity from 250 to 350 nm owing to the O^2--Eu3+ charge transfer band, irrespective of deposition temperature. Upon 312 nm excitation, the SnO²:Eu³⁺ thin films showed a main emission peak at 592 nm arising from the ⁵D₀→⁷F₁ transition and a weak 615 nm red band originating from the ⁵D₀→⁷F₂ transition of Eu³⁺. As the deposition temperature increased, the emission intensities of two bands increased rapidly, approached a maximum at 100 ℃, and then decreased slowly at 400 ℃. The thin film deposited at 200 ℃ exhibited a band gap energy of 3.81 eV and an average transmittance of 73.7% in the wavelength range of 500-1100 nm. These results indicate that the luminescent intensity of SnO²:Eu³⁺ thin films can be controlled by changing the deposition temperature.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.272-279
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• 2015

$Y_2O_3:Eu^{3+}$ is an excellent red-emitting phosphor, which has been widely used for display devices due to highly luminescent property and chemical stability. In this study, $Y_2O_3:Eu^{3+}$ red phosphors were prepared using the solid state reaction and RF thermal plasma synthesis. The particle size of $Y_2O_3:Eu^{3+}$ phosphors obtained by the solid state reaction varied from 10 to $20{\mu}m$, and 30~100 nanometer sized $Y_2O_3:Eu^{3+}$ particles were obtained from a liquid form of raw material through RF thermal plasma synthesis without an additional heat treatment. Photoluminescence measurements of the obtained $Y_2O_3:Eu^{3+}$ particles showed a red emission peak at 611 nm ($^5D_0{\rightarrow}^7F_2$). PL intensity of red nano phosphors prepared by RF thermal plasma synthesis was comparable to that of red phosphors prepared by the solid state reaction, indicating that nano-sized $Y_2O_3:Eu^{3+}$ red phosphors could be successfully synthesized using one-step process of RF thermal plasma.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.27-30
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• 2008

Nano-sized phosphor powders were synthesized by the liquid phase method to confirm the size and morphology. By using the process, red phosphor particles with a size of 80 nm were obtained. The characteristic comparison of $Y_2O_3:Eu^{3+}$ and $YBO_3:Eu^{3+}$ was carried out and, as a result, $YBO_3:Eu^{3+}$ powders using boric salt showed an aggregated morphology and lower PL performance compared to $Y_2O_3:Eu^{3+}$.

• Korean Journal of Materials Research
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• v.16 no.8
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• pp.485-489
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• 2006

The preparation conditions of $YBO_3$:Eu phosphor particles having the maximum photoluminescence intensity under vacuum ultraviolet in the spray pyrolysis were optimized. The $YBO_3$:Eu phosphor particles prepared from spray solution with stoichiometric amount of boric acid had the maximum photoluminescence intensity. The $YBO_3$:Eu phosphor particles with pure phases were formed at low post-treatment temperatures because of fast reaction of yttrium and boron components without volatilization of boron component. The prepared $YBO_3$:Eu phosphor particles by spray pyrolysis had fine size, narrow size distribution and regular morphology. The photoluminescence intensity of the prepared $YBO_3$:Eu phosphor particles under vacuum ultraviolet was 103% of the commercial $(Y,Gd)BO_3$:Eu phosphor particles.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.75-80
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• 1997

Preparation and properties of Eu(hfa)3·L (Hhfa = hexafluoroacetylacetone, L = bis(2-methoxyethyl)ether, diglyme, and 2, 2':6', 2"-terpyridine, tpy), which are potential CVD precursors for europium, were investigated. The reaction of the Eu2O3 with Hhfa in the presence of tridentate neutral ligand yielded the nine-coordinated Eu(hfa)3·L. Eu(hfa)3·diglyme is air- and moisture-stable and most importantly has good volatility and thermal stability. Eu(hfa)3·tpy shows no sublime intact. The complex Eu(hfa)3·diglyme has been characterized by an X-ray structure determination; monoclinic P21/n, a=10.252(1), b=16.051(6), c=19.392(8) Å, β=96.10(2)°, V=3173(2) Å3. The europium atom in Eu(hfa)3·diglyme adopts a square-antiprismatic geometry with the ninth coordinating oxygen atom capping one of the square faces. All the adducts have been characterized by IR, TGA/DTA.

• Korean Journal of Materials Research
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• v.22 no.3
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• pp.145-149
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• 2012

Red phosphors of $Gd_{1-x}Al_3(BO_3)_4:{Eu_x}^{3+}$ were synthesized by using the solid-state reaction method. The phase structure and morphology of the phosphors were measured using X-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM), respectively. The optical properties of $GdAl_3(BO_3)_4:Eu^{3+}$ phosphors with concentrations of $Eu^{3+}$ ions of 0, 0.05, 0.10, 0.15, and 0.20 mol were investigated at room temperature. The crystals were hexagonal with a rhombohedral lattice. The excitation spectra of all the phosphors, irrespective of the $Eu^{3+}$ concentrations, were composed of a broad band centered at 265 nm and a narrow band having peak at 274 nm. As for the emission spectra, the peak wavelength was 613 nm under a 274 nm ultraviolet excitation. The intensity ratio of the red emission transition ($^5D_0{\rightarrow}^7F_2$) to orange ($^5D_0{\rightarrow}^7F_1$) shows that the $Eu^{3+}$ ions occupy sites of no inversion symmetry in the host. In conclusion, the optimum doping concentration of $Eu^{3+}$ ions for preparing $GdAl_3(BO_3)_4:Eu^{3+}$ phosphors was found to be 0.15 mol.

• Journal of Sensor Science and Technology
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• v.11 no.6
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• pp.371-377
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• 2002

$Y_2O_3:Eu^{3+}$ and Li-doped $Y_2O_3:Eu^{3+}$ thin films have been grown on sapphire substrates using a pulsed laser deposition technique. The thin film phosphors were deposited at a substrate temperature of $600^{\circ}C$ under the oxygen pressure of 100, 200 and 300 mTorr. The films grown under different deposition conditions have been characterized using microstructural and luminescent measurements. The crystallinity and photoluminescence (PL) of the films are highly dependent on the oxygen pressure. The PL brightness data obtained from $Y_2O_3:Eu^{3+}$ films grown under optimized conditions have indicated that sapphire is one of the most promising substrate for the growth of high quality $Y_2O_3:Eu^{3+}$ thin film red phosphor. In particular, the incorporation of $Li^{+}$ ions into $Y_2O_3$ lattice could induce a remarkable increase of PL. The highest emission intensity was observed with LiF-doped $Y_{1.84}Li_{0.08}Eu_{0.08}O_3(Y_2O_3LiEu)$, whose brightness was increased by a factor of 2.7 in comparison with that of $Y_2O_3:Eu^{3+}$ films. This phosphor may promise for application to the flat panel displays.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.548-554
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• 1990

Temperature effects on the fluorescence emission spectra of 0.01 M Eu(III) ion with ClO$_4$, Cl$^-$, NO$_3$ were studied. Relative intensity change of hypersensitive band ($^5D0\; {\to}\;^7F_2$) and nonhypersensitive band ($^5D0 \;{\to}\;^7F_1$) was quite remarkable with temperature and ligand. The relative intensity change was interpreted as the change of formation constant and used to calculation the enthalpy change of $Eu(H_2O)_X^{3+}$+ to EuL(H$_2O)_{X-1}^{2+}$ complex. $\Delta{H}$ of $Eu(H_2O)_X^{3+}$ to EuCl(H$_2O)_{X-1}^{2+}$ was roughly 15 kJ/mol and temperature independent, but $\Delta{H}$ of EuNO$_3(H_2O)_{X-1}^{2+}$ was changed with temperature; -11 kJ/mol at 25$^{\circ}C$ and 47 kJ/mol at 250$^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1360-1363
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• 2006

A borate compound was adopted as new host material for $EU^{3+}$ activator. The $Eu^{3+}-doped\;YCa_3(GaO)_3(BO_3)_4$ (YCGB) phosphors were successfully synthesized. Also, their photoluminescence properties under the excitation of UV ray were measured. In the XRD patterns of the synthesized powders, most peaks were well-matched to a gaudefroyite phase. The emission of $Eu^{3+}$ in YCGB consists of a strong peak centered at 622 nm, which is attributed to $^5D_O-^7F_2$ transition of $Eu^{3+}$ and several weak peaks at near the wavelength. Optimum $Eu^{3+}$ concentration of the red phosphor under the excitation with the wavelength of 395 nm was about 75 mol%. This indicates that the red phosphor has a relatively higher critical concentration than that of the other $Eu^{3+}-doped$ phosphors. The dominant interaction character of $Eu^{3+}$ might be dipole-dipole interaction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1062-1065
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• 2003

본 연구에서는 초미세 $Y_2O_3:EU^{3+}$ 분말을 이용하여 나노 형광체를 제조하였다. 나노 형광체는 소량의 Eu가 도핑된 $Y_2O_3$ 재질로 구성되어 있다. 형광체 분말의 결정화를 위해 $500{\sim}900^{\circ}C$의 온도로 열처리하였다. 제조된 나노 형광체를 HRTEM으로 관찰한 결과 입자 크기가 열처리 온도에 따라 약 $4{\sim}30nm$의 분포를 나타내었다. 또한 XRD로 결정상을 분석한 결과 주로 입방정 구조로 되어 있고 소량의 단사정 구조가 포함된 $Y_2O_3$ peak가 검출되었다. EDS 분석 결과 약 $6.7{\sim}7.5%$의 Eu가 검출되었다. 약 4nm 크기의 $Y_2O_3:EU^{3+}$ 분말로 제조한 나노 형광체의 발광 특성은 주요 파장대가 612nm인 PL spectrum이 관찰되어, 적색 형광체로서의 $Y_2O_3:EU^{3+}$ 나노 분말이 제조되었다.