• 한국응용과학기술학회지
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• 제23권3호
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• pp.207-214
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• 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.

• 대한화학회지
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• 제46권4호
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• pp.336-345
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• 2002

본 연구에서는 조합화학을 이용하여 $CaO-Gd_2O_3-Al_2O_3$계에서 $Eu^{3+}$와 $Tb^{3+}$활성 적색 및 녹색 PDP용 형광체를 탐색하였으며 탐색된 형광체의 합성온도, 최적조성,발광 특성 등을 조사하였다. $CaO-Gd_2O_3-Al_2O_3$의 삼성분계의 형광특성 라이브러리를 작성하기 위하여 210개의 다른 조성을 가진 시료를 고분자 착체 중합법으로 합성하였다. 합성된 형광체 분말을 VUV PL로 측정하여 형광 특성 라이브러리를 작성하였고 발광특성이 잘 나타난 시료를 XPD를 이용하여 결정 구조를 확인하였다. 적색 형광체로서 탐색된 $Ca_{\alpha}$G$d_{0.95-\alpha-\beta}$$Al_\beta$$O_\delta$ : Eu(0.02< $\alpha+\beta$ <0.04)형광체는 색순도 면에서 상용형광체보다 개선된 특성을 보였으며 녹색 형광체로서 탐색된 $CaGdAl_3O_7$ : Tb, Ca$Al_{12}$$O_{19}$ : Tb, $Gd_4Al_2$$O_9$ : Tb, $Gd_3Al_5$$O_{12}$ : Tb 형광체 중에서 $CaGdAl_3O_7$ : Tb, Ca$Al_{12}$$O_{19}$ : Tb형광체는 상용 형광체에 비해 잔광시간이 짧은 특성을 보였다

• Applied Science and Convergence Technology
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• 제27권3호
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• pp.52-55
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• 2018

We reported a new method to enhance the photoluminescence (PL) properties of $Eu^{3+}$ ions doped $Gd_2Mo_4O_{15}$ phosphors via cation substitution. With the aid of conventional sol-gel method, a series of $Eu^{3+}$ ions doped $Gd_{2(1-x)}Y_{2x}Mo_4O_{15}$ phosphors were prepared. The prepared samples emitted red light when excited at 393 nm. Moreover, when part of the $Gd^{3+}$ ions was substituted by the $Y^{3+}$ ions, the PL emission intensity of the studied samples was enhanced and the optimal doping concentration for $Y^{3+}$ ions was 30 mol%. The calculated CIE coordinate (0.663,0.337) was situated in the red region. Furthermore, the thermal quenching behaviors of the synthesized $Eu^{3+}$ ions doped $Gd_{2(1-x)}Y_{2x}Mo_4O_{15}$ phosphors were studied. At last, we also packaged a red-emitting light-emitting diode device by integrating the obtained phosphors and a near-ultraviolet chip to verify the applications of the $Eu^{3+}$ ions doped $Gd_{2(1-x)}Y_{2x}Mo_4O_{15}$ phosphors for indoor lighting.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.344-344
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• 2007

본 연구에서는 X선 영상 검출기로의 적용을 위하여 $Gd_2O_3$:Eu 형광체 필름을 제작하여 X선에 대한 발광 특성을 분석하였다. $Gd_2O_3$:Eu는 저온 액상법을 이용하여 분말 형태로 제조한 후 Particle-in-binder (PIB)으로 필름 형태로 제작한 후, 도핑된 Europium(Eu)의 농도와 소결 온도에 따른 X선에 대한 발광 특성을 분석하였다. Photolumimescence (PL) spectrum에서 611nm에서 가장 높은 발광 효율을 나타내었으며, 입자의 크기가 줄어듦에 따라 610nm에서 새로운 peak가 형성 되었다. 또한 Eu의 농도에 따라서 발광 강도의 차이가 관찰되었는데, 5wt%의 도핑 농도에서 가장 높은 발광 효율을 나타냈으며, 도핑 농도에 매우 의존적인 결과를 나타냈다. 소결 온도에 따른 발광 특성 분석에서, $500^{\circ}C$에서 소결하였을 때는 623nm에서 강한 peak를 나타내는 단사정계상의 발광 peak는 거의 관찰되지 않았으나 소결 온도가 $700^{\circ}C$와 $900^{\circ}C$에서는 peak가 확인되었다. 이를 통해 $Gd_2O_3$ 모체가 대부분 입방 대칭 구조를 가지는 $Gd_2O_3$:Eu가 합성되었음을 확인할 수 있었다. 또한 소결 온도에 따른 발광 강도를 분석한 결과 $900^{\circ}C$에서 소결하였을 때 가장 높은 발광 강도를 나타냈다. Luminescent decay time 측정 결과에서 도핑된 Eu의 농도가 커질수록 Luminescent decay time이 짧아짐을 확인할 수 있었다.

• 한국세라믹학회지
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• 제55권5호
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• pp.461-472
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• 2018

$Gd_2O_3:Eu/Bi$ nanoparticles were synthesized via spray pyrolysis and applied for the preparation of a luminescent pearl pigment as an anti-counterfeiting material. The luminescence properties were optimized by changing the $Eu^{3+}$ and $Bi^{3+}$ concentration. Ethylene glycol was used as an organic additive to prepare the $Gd_2O_3:Eu/Bi$ nanoparticles. The highest emission intensity was achieved when the total dopant content was 10.0 at.% and the mole fraction of Bi was 0.1. The concentration quenching was mainly due to dipole-dipole interactions between the same activators, and the critical distances were 9.0 and $19.6{\AA}$ for $Eu^{3+}$ and $Bi^{3+}$, respectively. The prepared $Gd_2O_3:Eu/Bi$ powder exhibited an average size of approximately 82.5 nm and a narrow size distribution. Finally, the $Gd_2O_3:Eu/Bi$ nanophosphor coated on the surface of the pearl pigment was confirmed to have good red emission under irradiation from a portable ultraviolet light-emitting diode lamp (365 nm).

• 한국전기전자재료학회논문지
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• 제15권3호
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• pp.258-263
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• 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%.

• 한국방사선학회논문지
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• 제2권3호
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• pp.11-18
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• 2008

이 연구에서는 알코올과 증류수를 특정비율로 혼합한 특수용매를 사용하여 합성한 Gd2O3:Eu 나노 분말이 Europium(Eu)함량에 따라 어떤 입자특성과 발광특성을 가지게 되는지에 대하여 조사하였다. 액상법에 사용된 이 용매는 Gadolinium(Gd)과 Europium(Eu)의 용해되는 시간을 현저히 줄임으로써, 실험시간이 단축됨을 확인하였다. 이번 실험에서 Gd2O3:Eu 나노 powder 형광체의 입자특성은 SEM(scanning electron microscope)과 EDX(Energy Dispersive X-ray)를 사용하였으며, 나노 powder의 발광특성은 PL(Photoluminescence), CL(CathodeLuminescence)을 사용하여 측정하였다. 결정들은 30nm~40nm의 크기의 결정을 가졌고 발광특성은 약 620nm의 특정 파장에서 크게 반응함을 알 수 있었으며, Europium(Eu)함량이 1wt%에서 3wt%, 5wt%로 늘어날수록 Photon의 count가 증가하게 되어 발광효율이 증가함을 알 수 있었다.

• 한국재료학회지
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• 제12권10호
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• pp.771-775
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• 2002

$Gd_2$$O_3$:Eu phosphor particles with nano-sized and non-aggregation characteristics were prepared by spray pyrolysis using the spray solution containing polymeric precursor and $Li_2$$CO_3$ flux material. Nano-sized $Gd_2$$O_3$:Eu phosphor particles had higher brightness than the commercial $Y_2$$O_3$:Eu phosphor particles. The $Gd_2$$O_3$:Eu phosphor particles had nano-size and non-aggregation characteristics after heat-treatment at $1000^{\circ}C$ when the addition amount of $Li_2$$CO_3$ flux was 1 wt.% and 3 wt.%. The mean size of particles were 200 nm and 400 nm when the amount of flux was 1 wt.% and 3 wt.%, respectively. The prepared phosphor particles had higher photoluminescence intensity than that of the commercial product regardless of the content of$ Li_2$$CO_3$ flux and had the maximum brightness when the content of flux was 5 wt %. The photoluminescence intensity of the nano-sized $Gd_2$$O_3$:Eu phosphor particles containing 3 wt.% $Li_2$$CO_3$ flux was 125% in comparison with that of the micron-sized $Y_2$$O_3$:Eu commercial product.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.253-256
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• 2002

$Gd_2O_3$:Eu phosphor particles were prepared by largescale ultrasonic spray pyrolysis process. The morphological control of $Gd_2O_3$:Eu particles in spray pyrolysis was performed by adding polymeric precursors into spray solution containing nitrate salts. The effect of composition and amount of polymeric precursors on the morphology, crystallinity, and photoluminescence characteristics of $Gd_2O_3$:Eu particles was investigated. The influence of chain length of PEG on the morphology and photoluminescence intensity was investigated. $Gd_2O_3$:Eu particles prepared from aqueous solution containing no polymeric precursors had a hollow structure and rough surfaces after annealing process. The phosphor particles prepared from solution containing 0.1M CA and 0.lM PEG with high molecular weight as 1,500 had a spherical and filled morphology and the highest photoluminescence intensity, which was 48% higher than that of the $Y_2O_3$:Eu commercial product.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.148-152
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• 2007

In this paper, we have synthesized $Gd_2O_3:Eu^{3+}$ nano phosphor particle using a low temperature solution-combustion method. We have investigated the structure and the luminescent characteristic as the sintering temperature and europium concentration. From XRD(X-ray diffraction) and SEM(scanning electron microscope) results, we have verified that the phosphor particle was fabricated a spherical shape with $30{\sim}40nm$ particle size. From the photoluminescence results, the strong peak exhibits at 611 um and the luminescent intensity depends on europium concentration. $Gd_2O_3:Eu$ fine phosphor particle has shown excellent luminescent efficiency at 5 wt% of europium concentration. The phosphors calcinated at $500^{\circ}C$ have possessed the x-ray peaks corresponding to the cubic phase of $Gd_2O_3$. As calcinations temperature increased to $700^{\circ}C$, the new monoclinic phase has identified except cubic patterns. From the luminescent decay time measurements, mean lifetimes were $2.3{\sim}2.6ms$ relatively higher than conventional bulk phosphors. These results indicate that $Gd_2O_3:Eu$ nano phosphor is possible for the operation at the low x-ray dose, therefore, the application as medical imaging detector.