• 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 Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.3
• /
• pp.258-263
• /
• 2002

We present a new toed phosphor, $Gd_{2-x-y}Li_xEu_yO_3$ with superior luminescent Properties compared to the commercially available red phosphor $Y_2O_3:Eu^{3+}$. The phosphor, with a diameter of about $2\mu\textrm{m}$, consists of the psedospherical particles in a regular array. The photoluminescence measurements as a function of the laser power and the Eu mole fraction were performed at zoom temperature The luminescence intensity linearly increases as both the laser power and the Eu mole fraction Increase. As for the dependence on cathodoluminescence, the incorporation of Eu and Li ions into $Gd_2O_3$ lattice brings about an increase in luminescent efficiency. The highest emission intensity for the phosphor occurs at the applied voltage of 500 V, its value is larger than that of $Y_2O_3:Eu^{3+}$ powder by 70%.

• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.619-624
• /
• 2003

The $Gd_{1.9-x}Li_{0.1}Eu_xO_3$ (x=0.02, 0.05, 0.08, and 0.12) powders (${\thickapprox}1{\mu}m$) synthesized by sol-gel method, whose surfaces are modified in a colloidal silica suspension (size of $SiO_2$ particles: ${\sim}30$ nm), have been fabricated to highly stable and effective luminescent films on the glass substrates. Thanks to the fused $SiO_2$ nano particles in the vicinity of the glass softening temperature (at around $700^{\circ}C$), $Gd_{1.9-x}Li_{0.1}Eu_xO_3$ powders are strongly attached onto the surface of glass substrate (>9H, pencil hardness tester). This simple and low-cost method to get $Gd_{1.9-x}Li_{0.1}Eu_xO_3$ phosphor films without any loss of luminescence brightness would promise for applications to display devices.

• Journal of Ceramic Processing Research
• /
• v.13 no.spc1
• /
• pp.6-9
• /
• 2012

Eu3+-doped RE2O3 (RE = Gd, Y and La) phosphors were prepared by solvothermal reaction method and their crystalline structure, phase transformation and surface morphologies were investigated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM). The obtained RE2O3:Eu3+ phosphors are nanocrystalline-sized. The luminescence properties of Eu3+ ions in different host materials, namely, Gd2O3, Y2O3 and La2O3 have been investigated. PACS number: 32.50.+d, 78.55.-m, 81.40.Tv.

• Journal of the Korean Society of Radiology
• /
• v.2 no.3
• /
• pp.11-18
• /
• 2008

In this study, the particle properties and luminescence properties of Gd2O3 nano powder with various Eu content were studied. Gd2O3:Eu nano powder was fabricated using special solvent which mixed the alcohol and the distilled water at specific ratio. This solvent by the solution method showed short fabrication time because solution time of Gd and Eu was reduced. From this experiment with Gd2O3:Eu, the particle properties og nano powder phosphor way analysed using SEM (scanning electron microscope) and EDX(Energy Dispersive X-ray). Also the luminescence properties of nano powder was measured using PL(Photoluminescence) and CL (CathodeLuminescence). The size of powder was 30nm~40nm. The magnitude of powder showed the best peak at 620nm. Among 1,3,5wt% of Eu content, the more Eu content was added in powder, the more photons wre generated. Also it shows luminescence efficiency was improved adding 5% of Eu content.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.1
• /
• pp.112-117
• /
• 2004

$Y_2$$_{-x}$G $d_{x}$ $O_3$:E $u^{3+}$(x=0.0, 0.3, 0.6, 1.0, 1.4) luminescent thin films have been grown on Si (100) substrates using pulsed laser deposition. The films grown under different deposition conditions have been characterized using microstructural and luminescent measurements. The crystallinity, the surface morphology and photoluminescence (PL) of the films are highly dependent on the amount of Gd. The photoluminescence (PL) brightness data obtained from $Y_2$$_{-x}$G $d_{x}$ $O_3$:E $u^{3+}$ films grown under optimized conditions have indicated that Si (100) is one of promised substrates for the growth of high quality $Y_2$$_{-x}$G $d_{x}$ $O_3$:E $u^{3+}$ thin film red phosphor. In particular, the incorporation of Gd into $Y_2$ $O_3$ lattice could induce a remarkable increase of PL. The highest emission intensity was observed with $Y_{1.35}$G $d_{0.60}$ $O_3$: $E^{3+}$, whose brightness was increased by a factor of 1.95 in comparison with that of $Y_2$ $O_3$:E $u^{3+}$ films.3+/ films.films.lms.

• Journal of the Korean Ceramic Society
• /
• v.43 no.1 s.284
• /
• pp.10-15
• /
• 2006

Photoluminescence (PL) and crystal structures of the $(l-x)CaWO_4-xLi_2WO_4$ binary system added with $Eu_2O_3$ activator have been characterized. The $CaWO_4\;and\;Li_2WO_4$ have the scheelite and phenakite structures respectively. The $CaWO_4-Li_2WO_4-Eu_2O_3$ phosphors show the red luminescence of 613 nm peak wavelength. The wavelength range of excitation spectral band is $380\~470$ nm with the peak wavelength of 397 nm. The $0.88(0.5CaWO_4-0.5Li_2WO_4)-0.12Eu_2O_3$ showed the most superior luminescence characteristics. The effect of co-doping elements such as $Al_2O_3$ and rare-earth oxides on PL has been characterized. The co-doping elements deteriorated the luminescence intensity except the $Al_2O_3$ and $Gd_2O_3$. The PL characteristics of $CaWO_4-Li_2WO_4-Eu_2O_3$ phosphors have been compared to those of the alkali europium double molybdates (tungstates) of scheelite-related structure such as $LiEu(MoO_4)_2$ and $CsEu(MoO_4)_2$. The crystal structures of $(l-y)[(l-x)CaWO_4-xLi_2WO_4]-yEu_2O_3$ phosphors have been characterized using XRD data and rietveld refinement.

• Journal of Powder Materials
• /
• v.24 no.6
• /
• pp.457-463
• /
• 2017

Nanosized $Gd_2O_3:Eu^{3+}$ red phosphor is prepared using a template method from metal salt impregnated into a crystalline cellulose and is dispersed using a bead mill wet process. The driving force of the surface coating between $Gd_2O_3:Eu^{3+}$ and mica is induced by the Coulomb force. The red phosphor nanosol is effectively coated on mica flakes by the electrostatic interaction between positively charged $Gd_2O_3:Eu^{3+}$ and negatively charged mica above pH 6. To prepare $Gd_2O_3:Eu^{3+}$-coated mica ($Gd_2O_3:Eu/mica$), the coating conditions are optimized, including the stirring temperature, pH, calcination temperature, and coating amount (wt%) of $Gd_2O_3:Eu^{3+}$. In spite of the low luminescence of the $Gd_2O_3:Eu/mica$, the luminescent property is recovered after calcination above $600^{\circ}C$ and is enhanced by increasing the $Gd_2O_3:Eu^{3+}$ coating amount. The $Gd_2O_3:Eu/mica$ is characterized using X-ray diffraction, field emission scanning electron microscopy, zeta potential measurements, and fluorescence spectrometer analysis.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.324-325
• /
• 2011

최근에 고효율의 적색 형광체를 합성하여 형광 램프, 음극선관, X-선 검출기, 전계 발광 디스플레이에 응용하기 위하여 다양한 모체 결정과 활성체를 도핑하는 연구가 활발히 진행되고 있다. 본 연구에서는 $GdNbO_4$ 모체 결정에 $Eu^{3+}$ 이온 활성체를 주입하여 합성함으로써 새로운 적색 형광체의 발광 세기와 입자의 형상을 최적화 시키고자 한다. 형광체 분말 시료의 제조는 Eu의 함량을 0, 0.05, 0.10, 0.15, 0.20 mol로 변화시키면서 고상 반응법을 이용하여 합성하였다. 초기 물질 Gd2O3 (99.99%), $Nb_2O_5$ (99.99%), $Eu_2O_3$ (99.9%)를 화학 적량으로 측량하고 에탄올과 ZrO2 볼과 함께 플라스틱 병에 넣어 400 rpm의 속도로 24시간 볼밀 작업을 수행한 후에, 혼합된 분말의 볼을 걸러내고 60$^{\circ}C$에서 20시간 동안 건조하였다. 건조된 시료를 막자 사발에 넣고 잘게 갈아서 체로 걸러낸 다음에 세라믹 도가니에 넣고 전기로에서 분당 5$^{\circ}C$씩 승온하여 500$^{\circ}C$에서 10시간 동안 1차 하소한 후에, 계속 온도를 승온시켜 1,200$^{\circ}C$에서 3시간 동안 소결하여 합성하였다. XRD 회절 패턴의 경우에, $Eu^{3+}$의 함량에 관계없이 모든 세라믹은 JCPDS (22-1104)에 제시된 회절상과 일치하는 사방정계의 결정 구조를 가짐을 확인할 수 있었다. 주 피크는 28.4$^{\circ}$에서 최대값을 갖는 (121)면에서 발생하는 회절 신호이었다(Fig. 1). 적색 형광체 분말의 광학 및 표면 특성은 PL, PLE와 SEM으로 조사되었으며, 세라믹 분말의 형광 특성과 결정 구조, 표면 형상에 대한 자세한 논의가 제시될 것이다.