• 한국재료학회지
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• 제10권1호
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• pp.49-54
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• 2000

PDP용의 새로운 녹색 $Al_3GdB_4O_{12}:Tb^{3+} 형광체와 Al_3GdB_4O_{12}:Eu_{3+}$ 적색형광체를 제조한 후 광특성을 분석하였다. 또한 이들 형광체의 발광특성을 상용품인 $Zn_2SiO_4:Mn^{2+}$ 녹색 형광체와 $(Y,Gd)BO_3: Eu^{3+}$ 적색의 PDP 형광체와 상호 비교하였다. 형광체는 $1150^{\circ}C$에서 4시간 동안 공상 반응으로 제조하였다. 147nm의 진공자외선 조사시 $Al_3GdB_4O_{12}:Tb^{3+}$(15mol%) 녹색 형광체의 발광휘도는 상용품 $Zn_2SiO_4: Mn^{2+}$ 보다 증가하였으나 색좌표는 상대적으로 저하되었다. 한편 $Al_3GdB_4O_{12}:Eu^{3+}$(15mol%) 적색 형광체의 발광 휘도는 상용품$(Y,Gd)BO_3: Eu^{3+}$ 보다 작았으나 CIE 색좌표는 일부 개선되었다. $Al_3GdB_4O_{12}$ 형광체는 $\lambda=160nm$에서 모체 흡수에 의한 강한 여기밴드가 있으며, 진공자외선 영역에서 $Al_3GdB_4O_{12}:Tb^{3+}$ 녹색형광체의 여기강도는 $Zn_2SiO_4: Mn^{2+}$ 보다 컸으나 $Al_3GdB_4O_{12}:Eu^{3+}$ 적색 형광체의 여기강도는 $(Y,Gd)BO_3: Eu^{3+}$ 보다는 작았다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.791-794
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• 2003

To synthesize $Gd_{2}O_{3}:Eu$ phosphor powder of nano size and high luminescence efficiency under UV (ultraviolet) and VUV (vacuum ultraviolet) light, organic additives such as citric acid and ethylene glycol and $Na_{2}CO_{3}$ flux were introduced in large-scale spray pyrolysis and critical conditions for forming nano-sized particles were investigated. The $Gd_{2}O_{3}:Eu$ phosphor particles prepared from solutions with organic additives such as citric acid and ethylene glycol had micron size and spherical shape. However, the particles prepared from polymeric precursor solution with $Na_{2}CO_{3}$ flux had nano size and non-aggregation characteristics. The as-prepared spherical particles with micron size turned into nano-sized particles during post-treatment by recrystallization process. The nano-sized $Gd_{2}O_{3}:Eu$ phosphor particles showed higher brightness than the commercial $Y_2O_3:Eu$ phosphor product under both UV light of 254nm and VUV light of 147 nm.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4642-4646
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• 2023

The Tb³⁺ or Eu³⁺-doped Lu₂Gd₁Ga₂Al₃O₁₂ phosphor were fabricated by funace at 1500 ℃ for 12 h using a solid state reaction. The XRD (X-ray diffraction_Panalytical X'Pert Pro) and FE-SEM (field emission scanning electron microscope) are measured to confirm the crystalline structure and surface morphology of the phosphor. The Tb³⁺-doped Lu₂Gd₁Ga₂Al₃O₁₂ phosphor emits the lights in 470~650 nm wavelength range due to transitions from ⁵D₄ to ⁷F_j. Therefore, it shows the green region in the CIE chromaticity diagram under both UV and X-rays excitations. The Eu³⁺-doped Lu₂Gd₁Ga₂Al₃O₁₂ phosphor emits the lights in 550~750 nm wavelength range because of ⁵D_i to ⁷F_j. The emission is confirmed to be in the red region using the CIE chromaticity diagram. The Tb³⁺ or Eu³⁺-doped Lu₂Gd₁Ga₂Al₃O₁₂ phosphor shows the characteristic f-f transition with a long decay time, which is about several milliseconds. They have the high efficiency of light emission for X-ray because of their high effective Z number (Z_eff = 58.5) and density. Therefore, they are very much promising phosphors for X-ray imaging application in medical fields.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.594-597
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• 1999

The new green and red phosphors for PDP application activated by T $b^{3+}$ and E $u^{3+}$ were synthesized, and their photoluminance properties were investigated. It was found that the brightness of $Al_3$Gd $B_4$ $O_{12}$ :T $b^{3+}$ green phosphor under 147nm VUV irradiation was higher than that of commercial Z $n_2$ $SiO_4$:M $n^{2+}$ phosphor. But the emitting intensity of A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ red phosphor was inferior to the commercial (Y,Gd)B $O_3$:E $u^{3+}$. $Al_3$Gd $B_4$ $O_{12}$ Phosphor had a strong excitation band at 160nm associated with the host absorption, and also the photoluminance excitation intensity of $Al_3$Gd $B_4$ $O_{12}$ :T $b^{3+}$ was higher than that of Z $n_2$ $SiO_4$:M $n^{2+}$, but the intensity of $Al_3$Gd $B_4$ $O_{12}$ :E $u^{3+}$ phosphor was smaller than (Y,Gd)B $O_3$:E $u^{3+}$ phosphor In the VUV range. C $e^{3+}$ co-doping in A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ and substitution of $Al^{3+}$ by G $a^{3+}$ A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ phosphor were tried, but they did not improved the optical property .d the optical property .ty .

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1355-1359
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• 2006

Due to its efficient red emission, $Eu^{3+}$ ion has been doped in various host materials. $GdCa_4B_3O_{10}:Eu^{3+}$ phosphor for red emission has been prepared by solid state reaction. Photoluminescence properties for the phosphor under UV and VUV excitation were investigated. The $GdCa_4B_3O_{10}:Eu^{3+}$ phosphor under both excitation conditions shows typical red emission spectrum centered at 611 nm with several weak peaks due to energy transfer from $^5D_O\;to\;^7F_J(J=1,2,3,4)$ of $Eu^{3+}$ ion. On the other hand, the activator content exhibiting the concentration quenching under UV and VUV irradiation is 10 mole% and 2.5 mole%, respectively.

• 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.

• 한국재료학회지
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• 제27권10호
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• pp.534-543
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• 2017

$Gd_2O_3:Eu^{3+}$ red phosphors were prepared by template method from crystalline cellulose impregnated by metal salt. The crystallite size and photoluminescence(PL) property of $Gd_2O_3:Eu^{3+}$ red phosphors were controlled by varying the calcination temperature and $Eu^{3+}$ mol ratio. The nano dispersion of $Gd_2O_3:Eu^{3+}$ was also conducted with a bead mill wet process. Dependent on the time of bead milling, $Gd_2O_3:Eu^{3+}$ nanosol of around 100 nm (median particle size : $D_{50}$) was produced. As the bead milling process proceeded, the luminescent efficiency decreased due to the low crystallinity of the $Gd_2O_3:Eu^{3+}$ nanoparticles. In spite of the low PL property of $Gd_2O_3:Eu^{3+}$ nanosol, it was observed that the photoluminescent property was recovered after re-calcination. In addition, in the dispersed nanosol treated at $85^{\circ}C$, a self assembly phenomenon between particles appeared, and the particles changed from spherical to rod-shaped. These results indicate that particle growth occurs due to mutual assembly of $Gd(OH)_3$ particles, which is the hydration of $Gd_2O_3$ particles, in aqueous solvent at $85^{\circ}C$.

• 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

• Korean Chemical Engineering Research
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• 제46권6호
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• pp.1075-1080
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• 2008

구연산 및 융제를 함유하는 분무용액으로부터 분무열분해법에 의해 속이 빈 전구체 분말들을 합성하고, 후열처리 과정을 거쳐 미세 $Gd_2O_3:Eu$ 형광체를 합성하였다. 구연산은 전구체 분말들의 다공성을 증대시킴으로써 후열처리 후에 미세 형광체 합성이 가능하게 하였다. 구연산을 첨가하지 않은 분무용액으로부터 합성된 형광체는 수 마이크론 크기를 가졌다. 융제는 형광체 분말의 크기와 자외선 하에서의 발광세기를 증대시켰다. 여러 가지 용제 중 휘도가 우수한 초미세 $Gd_2O_3:Eu$ 형광체 합성에는 $Li_2CO_3$가 적절하였다. $Li_2CO_3$ 융제의 첨가량이 형광체의 3 wt% 이하일 때 소성 온도 $1,050^{\circ}C$ 및 $1,050^{\circ}C$에서 합성된 형광체들은 서브마이크론 크기를 가졌다. 소성 온도 $1,050^{\circ}C$에서 얻어진 형광체의 발광 세기는 소성온도 $1,050^{\circ}C$에서 얻어진 형광체의 124%였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.151-154
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• 2003

The synthesis and luminescent properties of trivalent europium activated gadolinium oxide red phosphors by sol-gel process have been investigated. Aqueous metal nitrate solution was mixed with EDTA which was chosen by the most suitable material of sol-gel formation as chelating agents. We noticed that the samples when are heated with EDTA at a temperature of $100^{\circ}C$ for lhrs, produced brownish and crisp powders due to condensation reaction on decomposition, dehydration and formation of sol-gel. Hence, when the powder pre-heated at about $100^{\circ}C$ was then heated at $1200^{\circ}C$ for 3hrs in atmosphere, the luminescence properties of resultant $Gd_{2}O_{3}:Eu^{3+}$ phosphor was measured by SEM, FT-IT and brightness intensity was shown 20% higher than those prepared by conventional method and by other chelating agent.