• Title/Summary/Keyword: $Eu^{2+}$-doped phosphor

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Luminescence Characteristics of Mg2+·Ba2+ Co-Doped Sr2SiO4:Eu Yellow Phosphor for Light Emitting Diodes (LED용Mg2+·Ba2+Co-Doped Sr2SiO4:Eu 노란색 형광체의 발광특성)

  • Choi, Kyoung-Jae;Jee, Soon-Duk;Kim, Chang-Hae;Lee, Sang-Hyuk;Kim, Ho-Kun
    • Journal of the Korean Ceramic Society
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    • v.44 no.3 s.298
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    • pp.147-151
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    • 2007
  • An improvement for the efficiency of the $Sr_{2}SiO_{4}:Eu$ yellow phosphor under the $450{\sim}470\;nm$ excitation range have been achieved by adding the co-doping element ($Mg^{2+}\;and\;Ba^{2+}$) in the host. White LEDs were fabricated through an integration of an blue (InGaN) chip (${\lambda}_{cm}=450\;nm$) and a blend of two phosphors ($Mg^{2+},\;Ba^{2+}\;co-doped\;Sr_{2}SiO_{4}:Eu$ yellow phosphor+CaS:Eu red phosphor) in a single package. The InGaN-based two phosphor blends ($Mg^{2+},\;Ba^{2+}\;co-doped\;Sr_{2}SiO_{4}:Eu$ yellow phosphor+CaS:Eu red phosphor) LEDs showed three bands at 450 nm, 550 nm and 640 nm, respectively. The 450 nm emission band was due to a radiative recombination from an InGaN active layer. This 450 nm emission was used as an optical transition of the $Mg^{2+},\;Ba^{2+}\;co-doped\;Sr_{2}SiO_{4}:Eu$ yellow phosphor+CaS:Eu red phosphor. As a consequence of a preparation of white LEDs using the $Mg^{2+},\;Ba^{2+}\;co-doped\;Sr_{2}SiO_{4}:Eu$ yellow phosphor+CaS:Eu red phosphor yellow phosphor and CaS:Eu red phosphor, the highest luminescence efficiency was obtained at the 0.03 mol $Ba^{2+}$ concentration. At this time, the white LEDs showed the CCT (5300 K), CRI (89.9) and luminous efficacy (17.34 lm/W).

Synthesis of Barium Hexaaluminate Phosphros Using Combinatorial Chemistry (조합화학을 이용한 망간(2+)과 유로피움)2+)이 첨가된 Barium Hexaaluminate 형광체의 합성 및 광특성 분석)

  • 박응석;최윤영;손기선;김창해;박희동
    • Journal of the Korean Ceramic Society
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    • v.37 no.2
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    • pp.134-139
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    • 2000
  • The main objective of the present investigation is to show the feasibility of combinatorial chemistry by applying this method to phosphor syntehses. In this respect barium hexaaluminate phosphor was prepared by the split-pool combinatorial method, which enabled much more rapid search of optimum compositions of target phosphors than conventional synthetic methods. Barium hexaaluminate phosphors doped with Eu2+ exhibit blue emission while those co-doped with Mn2+ and Eu2+ exhibit green emission. Basically, the phosphor doped with 1.3 mole of Ba and 0.06~0.15 mole of Eu2+ exhibit the maximum value of emission intensity at 435${\mu}{\textrm}{m}$. Under the UV and VUV extitations, the barium hexaaluminate phosphor co-doped with Mn2+ and Eu2+ shows strong green emission.

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UV pumped three color phosphor blend White emitting LEDs

  • Choi, Kyoung-Jae;Park, Joung-Kyu;Kim, Kyung-Nam;Kim, Chang-Hae;Kim, Ho-Kun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1338-1342
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    • 2005
  • We have synthesized an $Eu^{2+}$-activated $Sr_3MgSi_2O_8$ blue phosphor and $Ba_2SiO_4$ green phosphor and $Ba^{2+}$ co-doped $Sr_3SiO_5$ red phosphor investigated an attempt to develop white LEDs by combining it with a GaN blue LED $chip(\lambda_{em}=405 nm)$. Three distinct emission bands from the GaN-based LED and the $(Sr_3MgSi_2O_8:Eu\; +\; Ba_2SiO_4:Eu\; +\; Ba^{2+}\; co-doped\; Sr_3SiO_5:Eu)$ phosphor are clearly observed at 460nm, 520 nm and at around 600 nm, respectively. These three emission bands combine to give a spectrum that appears white to the naked eye. Our results show that GaN (405 nm chip)-based $(Sr_3MgSi_2O_8:Eu\; +\; Ba_2SiO_4:Eu\; +\; Ba^{2+}\; co-doped\; Sr_3SiO_5:Eu) exhibits a better luminous efficiency than that of the industrially available product InGaN (460 nm chip)-based YAG:Ce.

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Luminescent Characteristics and Synthesis of Eu3+- Doped Y2O3 Red Phosphors (Y2O3 : Eu3+ 적색 형광체의 발광특성)

  • Yu, Il
    • Korean Journal of Materials Research
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    • v.31 no.10
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    • pp.582-585
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    • 2021
  • Y2O3:Eux (x = 0.005, 0.01, 0.02, 0.03, 0.05, 0.1 mol) phosphors are synthesized with different concentrations of Eu3+ ions by solvothermal method. The crystal structure, surface and optical properties of the Eu doped Y2O3 phosphors are investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) and photoluminescence excitation (PLE) analyses. From X-ray diffraction (XRD) results, the crystal structure of the Eu doped Y2O3 phosphor is found to be cubic. The maximum emission spectra of the Eu doped Y2O3 phosphors are observed at 0.05 mol Eu3+ concentration. The photoluminescence of 615 nm in the Eu doped Y2O3 phosphors is associated with 5D07F2 transition of Eu3+ ions. The decrease in emission intensity of 0.1 mol Eu doped Y2O3 is interpreted by concentration quenching. The International Commission on Illumination (CIE) coordinates of 0.05 mol Eu doped Y2O3 phosphor are X = 0.6547, Y = 0.3374.

The luminescence properties of Eu3+ or Tb 3+ doped Lu2Gd1Ga2Al3O12 phosphors for X-ray imaging

  • M.J. Oh;Sudipta Saha;H.J. Kim
    • Nuclear Engineering and Technology
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    • v.55 no.12
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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 7Fj. 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 5Di to 7Fj. 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 (Zeff = 58.5) and density. Therefore, they are very much promising phosphors for X-ray imaging application in medical fields.

Synthesis and photoluminescence of Ca3Si3O8F2: Ce4+, Eu3+, Tb3+ phosphor

  • Suresh, K.;PoornachandraRao, Nannapaneni V.;Murthy, K.V.R.
    • Advances in materials Research
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    • v.3 no.4
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    • pp.227-232
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    • 2014
  • $Ce^{4+}$, $Eu^{3+}$, $Tb^{3+}$ co-doped $Ca_3Si_3O_8F_2$ phosphor was synthesized via solid state reaction method using $CaF_2$, $CaCO_3$ and $SiO_2$ as raw materials for the host and $Eu_2O_3$, $CeO_2$, and $Tb_4O_7$ as activators. The luminescent properties of the phosphor was analysed by spectrofluorophotometer at room temperature. The effect of excitation wavelengths on the luminescent properties of the phosphor i.e. under near-ultraviolet (nUV) and visible excitations was investigated. The emission peaks of $Ce^{4+}$, $Eu^{3+}$, $Tb^{3+}$ co-doped $Ca_3Si_3O_8F_2$ phosphor lays at 480(blue band), 550(green band) and 611nm (red band) under 380nm excitation wavelength, attributed to the $Ce^{4+}$ ion, $Tb^{3+}$ ion and $Eu^{3+}$ ions respectively. The results reveal that the phosphor emits white light upon nUV (380nm) / visible (465nm) illumination, and a red light upon 395nm / 535nm illumination. RE ions doped $Ca_3Si_3O_8F_2$ is a promising white light phosphor for LEDs. The emission colours can be seen using Commission international de l'eclairage (CIE) co-ordinates. A single host phosphor emitting different colours under different excitations indicates that it is a potential phosphor having applications in many fields.

Synthesis and Characterization of $Eu^{2+}$ Doped $BaAl_2S_4$ Phosphor by Vacuum Heat Treatment

  • Cho, Yang-Hwi;Park, Do-Hyung;Ahn, Byung-Tae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.39-42
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    • 2006
  • A $Eu^{2+}$ doped $BaAl_2S_4$ phosphor was synthesized from BaS, EuS, Al and S powder by vacuum heat treatment. The synthesized powder at $850^{\circ}C$ was composed of only $BaAl_2S_4$ phase. The photoluminescence of $Eu^{2+}$ doped $BaAl_2S_4$ phosphor showed the blue emission centered at 470nm and CIE color coordinate at x=0.12, y=0.11.

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UV pumped two color phosphor blend White emitting LEDs

  • Choi, Kyoung-Jae;Park, Joung-Kyu;Kim, Kyung-Nam;Kim, Chang-Hae;Kim, Ho-Kun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.636-639
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    • 2004
  • We have synthesized a $Eu^{2{\cdot}}$ -activated $Sr_3MgSi_2O_8$ blue phosphor and $Ba^{2{\cdot}}$ co-doped $Sr_2SiO_4$ yellow phosphor investigated an attempt to develop white LEDs by combining it with a GaN blue LED chip. Three distinct emission bands from the GaN-based LED and the ($Sr_3MgSi_2O_8$:Eu + $Ba^{2{\cdot}}$ co-doped $Sr_2SiO_4$:Eu) phosphor are clearly observed at 405nm, 455 nm and at around 540 nm, respectively. These three emission bands combine to give a spectrum that appears white to the naked eye. Our results show that GaN (405 nm chip)-based ($Sr_3MgSi_2O_8$:Eu + $Ba^{2{\cdot}}$ co-doped $Sr_2SiO_4$:Eu) exhibits a better luminous efficiency than that of the industrially available product InGaN (460 nm chip)-based YAG:Ce.

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Luminescence of $Eu^{3+}-doped\;GdCa_4B_3O_{10}$ phosphor under UV and VUV irradiation

  • Oh, Jae-Suk;Kwak, Chung-Heop;Jung, Ha-Kyun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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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.

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Effects of Oxygen and Alkaline Earth Atoms on Emission Wavelength of $Eu^{2+}$-doped Oxide Phosphor: A Computational Chemistry Study

  • Onuma, Hiroaki;Yamashita, Itaru;Serizawa, Kazumi;Suzuki, Ai;Tsuboi, Hideyuki;Hatakeyama, Nozomu;Endou, Akira;Takaba, Hiromitsu;Kubo, Momoji;Miyamoto, Akira
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.294-297
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    • 2009
  • We computationally investigated the effects of oxygen and alkaline-earth on the emission wavelength of the $Eu^{2+}$-doped oxide phosphor. Using QSPR method, we found that the oxygen and alkaline-earth atom around the Eu atom increase and decrease the emission wavelength, respectively. We also investigated the $Eu^{2+}$-doped sulfide, nitride, and oxynitride phosphors.

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