Luminescence properties of R2MoO6:Eu3+ (R = Gd, Y, La) phosphors prepared by Pechini sol-gel process

2005 ◽  
Vol 20 (10) ◽  
pp. 2676-2681 ◽  
Author(s):  
Maolin Pang ◽  
Xiaoming Liu ◽  
Jun Lin
Keyword(s):  
Grain Size ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
X Ray ◽  
Average Grain Size ◽  
Sem Study ◽  
Sol Gel Process

R2MoO6:Eu3+ (R = Gd, Y, La) phosphors were prepared by the Pechini sol-gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), reflectance spectra, photoluminescence (PL) spectra, and lifetimes were used to characterize the resulting phosphors. The results of XRD indicate that all of the R1.96Eu0.04MoO6 (R = Gd, Y, La) phosphors crystallized completely at 800 °C. Y1.96Eu0.04MoO6 and Gd1.96Eu0.04MoO6 are of isomorphous monoclinic (α) structure, while La1.96Eu0.04MoO6 preferentially adopts the tetragonal (γ) form. FE-SEM study reveals that the samples mainly consist of aggregated particles with an average grain size ranging from 100 to 250 nm. The luminescent properties of R2MoO6:Eu3+ (R = Gd, Y, La) phosphors are largely dependent on their structure, grain size, and powder morphology. The isomorphous Y2MoO6:Eu3+ and Gd2MoO6:Eu3+ phosphors show very similar luminescence properties, which differ greatly from that of the La2MoO6:Eu3+ phosphor.

Sol-Gel Deposition and Luminescence Properties of Spherical Phosphors Ca2Y8(SiO4)6O2:Eu3+

2008 ◽  
Vol 368-372 ◽  
pp. 378-380
Author(s):  
Xiu Mei Han ◽  
J. Lin ◽  
M. Yu ◽  
C.K. Lin ◽  
Xi Wei Qi ◽  
...  
Keyword(s):  
Grain Size ◽  
Charge Transfer ◽  
Diffraction Analysis ◽  
Charge Transfer Band ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Red Emission ◽  
X Ray ◽  
Average Grain Size ◽  
Sol Gel Process

Spherical SiO2 particles were coated with Ca2Y8(SiO4)6O2:Eu3+ phosphor layers through a sol-gel process. The results of XRD (X-ray diffraction) analysis indicated that the phosphors crystallized completely at 1000oC. AFM study revealed that the average grain size is 500 nm. In Ca2Y8(SiO4)6O2:Eu3+ spherical phosphors , the Eu3+ showed its characteristic red emission at 612 nm(5D0-7F2) upon excitation into its charge transfer band of Eu3+-O2- at 242nm.

Luminescent Properties of Zn2SiO4:Eu3+,Dy3+ Phosphors via Sol-Gel Process

2012 ◽  
Vol 217-219 ◽  
pp. 733-736
Author(s):  
Xiu Mei Han ◽  
Shu Ai Hao ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectra ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir

Zn2SiO4:Eu3+, Dy3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1000oC. In Zn2SiO4:Eu3+,Dy3+ phosphors, the Eu3+ and Dy3+ show their characteristic red(613nm, 5D0-7F2), blue (481nm, 4F9/2–6H15/2) and yellow (577nm, 4F9/2–6H13/2) emissions.

Photoluminescence Characteristics of Sol–Gel Derived ZnTiO3 Doped with Ni2+ Ion

2013 ◽  
Vol 544 ◽  
pp. 360-363 ◽  
Author(s):  
You Hua Yu ◽  
Meng Xia ◽  
Li Li Liu ◽  
Wei Jie Wu
Keyword(s):  
Sol Gel ◽  
Luminescent Properties ◽  
Host Lattice ◽  
Deionized Water ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
Spectra Analysis ◽  
X Ray ◽  
Water As Solvent ◽  
Sol Gel Process

ZnTiO3 doped with Ni 2+ ion has been prepared at a relatively low temperature of 600°C from the precursor derived from sol-gel process using deionized water as solvent. X-ray diffraction analysis indicates that the doped samples exhibit a hexagonal ZnTiO3 structure. From the luminescence spectra analysis, the introduction of Ni2+ ions into ZnTiO3 results in novel luminescent properties. And the relative intensity of the bands varies with the concentration of Ni2+ ions. It is demonstrated that the Ni2+ ion has taken the place of Zn2+ ion in the host lattice of ZnTiO3.

Mechanical Alloying of Fe30Cu70

2007 ◽  
Vol 23 ◽  
pp. 63-66
Author(s):  
Virgiliu Călin Prică ◽  
George Arghir
Keyword(s):  
Grain Size ◽  
Milling Time ◽  
Mixing Enthalpy ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
X Ray ◽  
A Value ◽  
Average Grain Size ◽  
Milling Duration ◽  
Time Changes

Fe-Cu system is a binary alloys system, nevertheless very difficult. This paper presented the milling duration influence on ball-milled Fe30Cu70 alloys. After 16 hour of milling it has been concluded that true alloying at atomic level occurs during milling. The average grain size depends by milling time. Varying the milling time changes the powder morphology, their size and structure. We found that the complete fcc Fe –Cu solid solution is formed when the grain size of Fe-bcc reach a value about 10 nm, because at this value of crystallite the free energy for interface become less than interfaces energy. The milling duration have a strongly influence on solid solubility and phases form in Fe-Cu system. The phase formation for Fe30Cu70 (mass %) has been investigated by X-ray diffraction (XRD). The mixing enthalpy (positive in this system) also depends on alloy composition.

Synthesis and Characterization of Nanocrystalline PZT Powders by a Simple Sol-Gel Method

2012 ◽  
Vol 512-515 ◽  
pp. 147-152
Author(s):  
Shao Peng Zhang ◽  
Xiao Hui Wang ◽  
Long Tu Li
Keyword(s):  
Grain Size ◽  
Lead Zirconate Titanate ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Average Grain Size

Nanocrystalline lead zirconate titanate (PZT) powders with composition at the morphotropic phase boundary (MPB) were synthesized by a simple aqueous based sol-gel method, using lead nitrate, zirconium nitrate and tetrabutyl titanate as the starting materials. The sol could be easily transformed into gel, firstly heated at 120°C for 10h, then at 180°C for 24h. The thermal decomposition process of the gel was investigated by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The effect of citrate addition amount on the calcining temperature was discussed. The results reveal that pure perovskite phase PZT powders can be obtained at a calcining temperature as low as 600°C. The average grain size of the powders was determined by transmission electron microscope and X-ray diffraction. The influences of calcining temperature and the pH value of the solution on the grain size were investigated. The sintering temperature and electrical properties of the ceramics derived by nano-powders were compared with those prepared by the conventional ceramic processing. The result shows that using the nanopowder, the sintering temperature could be reduced by about 100°C and the ferroelectric properties were enhanced.

Synthesis and Luminescent Properties of Monodisperse Spherical SiO2/Ca10(PO4)6(OH)2: Eu3+ Particles with Core-Shell Structure

2014 ◽  
Vol 1004-1005 ◽  
pp. 344-347
Author(s):  
Huan Wang
Keyword(s):  
Smooth Surface ◽  
Calcium Phosphates ◽  
Sol Gel ◽  
Spherical Shape ◽  
Luminescent Properties ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Shell Particles

The growing necessity of biomaterials has increased the interest in calcium phosphates, particularly hydroxyapatite. In this paper, monodisperse and spherical SiO2particles have been coated with Ca10(PO4)6(OH)2:Eu3+layers via a Pechini sol-gel process, resulting in core-chell ctructured SiO2/Ca10(PO4)6(OH)2:Eu3+samples. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra were employed to characterize the SiO2/Ca10(PO4)6(OH)2:Eu3+core-shell particles. The resulted core-shell particles have perfect spherical shape with narrow size distribution, smooth surface and non-agglomeration.

Structure and Magneto-Resistance in Nanostructured Sr2Fe1-xCrxMoO6 (0≤x≤0.3) Double Perovskite Componds

2011 ◽  
Vol 130-134 ◽  
pp. 3298-3301
Author(s):  
Xiang Hu Li ◽  
Dan Li
Keyword(s):  
Grain Size ◽  
Sol Gel ◽  
Double Perovskite ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
X Ray ◽  
Average Grain Size ◽  
Diffraction Patterns ◽  
Magneto Resistance ◽  
Fe Substitution

The compounds of Fe substitution of Cr in nanotructured Sr2Fe1-xCrxMoO6(0≤x≤0.3) double perovskite have been prepared by sol-gel method. The x-ray diffraction patterns of the samples show that the samples are in nanometer range. And the average grain size D for these samples is 39.7, 37.1, 33.4, 31.9, and 31.2nm, respectively, decreases with the increasing of Cr ion. The saturation magnetization and the magnetoresistance of the samples decrease with the increasing of Cr for the disorder defects which increase for the close ionic radii of Mo and Cr.

A CRYSTAL STRUCTURE STUDY OF La1-xCaxMnO3 NANOPARTICLES

2004 ◽  
Vol 18 (12n13) ◽  
pp. 597-602 ◽  
Author(s):  
YINGWEN DUAN ◽  
JIANGONG LI
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Surface Effect ◽  
Sol Gel ◽  
Structure Study ◽  
X Ray Diffraction ◽  
Structure Transition ◽  
X Ray ◽  
Grain Sizes ◽  
Average Grain Size

Using a sol-gel method, La 1-x Ca x MnO 3(0≤x≤0.5) nanoparticles with nearly the same average grain size of about 21 nm and different Ca contents, La 0.8 Ca 0.2 MnO 3 nanoparticles with various average grain sizes were prepared. Crystal structure was investigated by X-ray diffraction. Increasing Ca content and decreasing grain size can lead to the average Mn–O bond lengths decrease and Mn–O–Mn bond angles increase. The crystal symmetry changes from orthorhombic to cubic as x≥0.3 for the La 1-x Ca x MnO 3(0≤x≤0.5) nanoparticles with nearly the same average grain size and D~16 nm for the La 0.8 Ca 0.2 MnO 3 nanoparticles with various grain sizes. Small-size effect and surface effect may be the reasons of the lattice distortion and structure transition.

Luminescent Properties of MgLaLiSi2O7:Eu3+ Phosphors via Sol-Gel Process

2012 ◽  
Vol 512-515 ◽  
pp. 178-181
Author(s):  
Xiu Mei Han ◽  
Deng Hui Ren ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectra ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir ◽  
The Eu

MgLaLiSi2O7:Eu3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. FT-IR spectra suggested that crystallized silicates have formed in the powders annealed at 1050°C. The results of XRD indicated that the phosphors crystallized completely at 1050°C. In MgLaLiSi2O7:Eu3+ phosphors, the Eu3+ shows its characteristic red (613nm, 5D0–7F2) emissions.

Sol-Gel derived Bi4-xNdxTi3O12 Thin Films and Their Characterization

2002 ◽  
Vol 737 ◽  
Author(s):  
R.E. Melgarejo ◽  
M.S. Tomar ◽  
A. Hidalgo ◽  
R.S. Katiyar
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complete Solid Solution ◽  
Sol Gel Process ◽  
Ferroelectric Memory ◽  
Initial Results

ABSTRACTNd substituted bismuth titanate Bi4-xNdxTi3O12 were synthesized by sol-gel process and thin films were deposited on Pt substrate (Pt/TiO2/SiO2/Si) by spin coating. Thin films, characterized by X-ray diffraction and Raman spectroscopy, shows complete solid solution up to the composition x < 1. Initial results indicate that the ferroelectric polarization increases with increasing Nd content in the film with 2Pr = 50μC/cm2 for x = 0.46, which may have application in non-volatile ferroelectric memory devices.

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