Luminescence Properties of Spherical Phosphors SrSiO3:Eu3+

2007 ◽  
Vol 336-338 ◽  
pp. 619-621 ◽  
Author(s):  
Xiu Mei Han ◽  
J. Lin ◽  
M. Yu ◽  
C.K. Lin ◽  
Xi Wei Qi ◽  
...  
Keyword(s):  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Red Emission ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Sio2 Particles

Spherical SiO2 particles have been successfully coated with SrSiO3:Eu3+ phosphor layers through a sol-gel process. The resulted core-shell phosphors were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence spectra as well as kinetic decays. The XRD results demonstrate that the SrSiO3:Eu3+ layers begin to crystallize on the SiO2 particles after annealing at 1000oC. The obtained core-shell phosphors have perfect spherical shape. The Eu3+ shows a strong photoluminescence (PL) (dominated by 5D0-7F2 red emission at 612 nm).

Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core–Shell Structured Spherical Phosphors by Sol–Gel Process

2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Average Size

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

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.

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.

Low-Temperature Synthesis of Nano-Crystalline ZnTiO3 Powders by Aqueous Sol-Gel Process

2014 ◽  
Vol 543-547 ◽  
pp. 3741-3744
Author(s):  
Quan Jing Mei ◽  
Cong Ying Li ◽  
Jing Dong Guo ◽  
Gui Wang ◽  
Hai Tao Wu
Keyword(s):  
Sol Gel ◽  
Zinc Nitrate ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Calcination Process ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Sol Gel Process

The ecandrewsite-type ZnTiO3was successfully synthesized by the aqueous sol-gel method using TiO2dioxide and zinc nitrate as starting materials instead of expensive organic solvent and metal alkoxides. The as-prepared nanopowders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and transmission electron microscopy (TEM), respectively. The results showed that the calcination process of gel consisted of a series of oxidation and combustion reactions, accompanied by significantly exothermal effects. Highly reactive nanosized ZnTiO3powders were successfully obtained at 850 °C with particle size ~50 nm. By comparison, the aqueous sol-gel process was the most effective and least expensive technique used for the preparation of ZnTiO3nanopowders.

Sol-gel derived Ba(Mg1/3Ta2/3)O3 thin films: Preparation and structure

1997 ◽  
Vol 12 (3) ◽  
pp. 596-599 ◽  
Author(s):  
Ji Zhou ◽  
Qing-Xin Su ◽  
K. M. Moulding ◽  
D. J. Barber
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Small Grains

Ba(Mg1/3Ta2/3)O3 thin films were prepared by a sol-gel process involving the reaction of barium isopropoxide, tantalum ethoxide, and magnesium acetate in 2-methoxyethanol and subsequently hydrolysis, spin-coating, and heat treatment. Transmission electron microscopy, x-ray diffraction, and Raman spectroscopy were used for the characterization of the thin films. It was shown that the thin films tend to crystallize with small grains sized below 100 nm. Crystalline phase with cubic (disordered) perovskite structure was formed in the samples annealed at a very low temperature (below 500 °C), and well-crystallized thin films were obtained at 700 °C. Although disordered perovskite is dominant in the thin films annealed below 1000 °C, a low volume fraction of 1 : 2 ordering domains was found in the samples and grows with an increase of annealing temperature.

Investigation on Nano-Sized ZnO Powder Doped with Al3+ Prepared by Sol-Gel Method

2012 ◽  
Vol 621 ◽  
pp. 3-7
Author(s):  
Yu Xiong ◽  
Ji Zheng ◽  
Song Lin Li ◽  
Xue Jia Liu ◽  
Lu Liang
Keyword(s):  
Electron Microscope ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Doped Zno ◽  
Zno Powder ◽  
Tin Tetrachloride

Al3+-doped ZnO nano-powder was prepared by sol-gel process, using tin tetrachloride and titanium tetrachloride as starting materials. The crystallinity and purity of the powder were analyzed by X-ray diffraction spectrometer (XRD). And the size and distribution of Al3+-doped ZnO grains were studied using transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the Al3+ was successfully doped into the crystal lattice of tin oxide and that the electric conductivity of Al3+-doped ZnO sample was improved significantly.

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.

Preparation of Alumina Powders through Pyrocatechol, Resorcinol Mediated Sol-Gel Method

2016 ◽  
Vol 850 ◽  
pp. 742-747
Author(s):  
Xiang Zhang ◽  
Ping Yun Li ◽  
Xiao De Guo ◽  
Ting Yan
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Xrd Study ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Scanning Electron ◽  
Organic Monomer

Ultrafine alumina powders were synthesized through pyrocatechol and resorcinol mediated sol-gel process. Aluminum nitrate was applied as the Al source and PVP was the dispersant. X-ray diffraction (XRD) study displayed that γ-Al2O3 powders formed in the range of 800-900 °C, and then γ-Al2O3 transformed to α-Al2O3 at higher temperatures, pure α-Al2O3 powders could be obtained at 1000 °C by using resorcinol as organic monomer. The results of transmission electron microscopy (TEM) revealed that Al2O3 nanoparticles with γ crystalline phase had grain sizes in the range of 5-40 nm. Scanning electron microscopy (SEM) observation displayed that the morphology of the prepared α-Al2O3 powders had aggregated bodies formed by Al2O3 grains in the range of 0.2-0.5μm. These results provide a new way of preparation of alumina powders.

Preparation of luminescent inorganic core/shell-structured nanoparticles

2011 ◽  
Vol 1342 ◽  
Author(s):  
Moritz Milde ◽  
Sofia Dembski ◽  
Sabine Rupp ◽  
Carsten Gellermann ◽  
Gerhard Sextl ◽  
...  
Keyword(s):  
Sol Gel ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Coating Solution ◽  
Transmission Electron ◽  
Composition And Structure ◽  
Sol Gel Process ◽  
Shell Composition ◽  
Diffraction Patterns ◽  
Process Annealing

ABSTRACTSiO2 nanoparticles (NPs) were coated with Eu3+-doped calcium phosphate (CP) and Mn2+-doped ZnO to give Zn2SiO4 via a modified Pechini sol-gel process. Annealing at high temperatures resulted in NPs with an amorphous core and a crystalline luminescent shell. It was shown that this procedure can be applied to silica cores with diameters below 300 nm. By transmission electron microscopy, elemental analysis and from X-ray diffraction patterns it was determined that shell composition and structure are influenced by the annealing temperature and pH of the coating solution. Measurements of photoluminescence intensities displayed their dependency on the concentration of dopant in the resulting core/shell NPs.

Synthesis of SnO2 by Sol-Gel Method

2016 ◽  
Vol 254 ◽  
pp. 200-206 ◽  
Author(s):  
Catalina Nuțescu Duduman ◽  
María Isabel Barrena Pérez ◽  
José Maria Gómez de Salazar ◽  
Ioan Carcea ◽  
Daniela Lucia Chicet ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Diffraction Pattern ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Transmission Electron ◽  
Sol Gel Process

Nanostructured SnO2 was prepared based on the sol-gel method used in the preparation of crystalline metal oxides. Sol-gel process can be described as a forming network of oxide polycondensation reaction of a molecular precursor in a liquid. Six experiments were carried out. Morphological structures and chemical composition were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) after calcination. It is noted that TEM images show that the spheres consist from nanocrystals, quantitative EDS analysis of the chemical composition shows an absence of the chlorine, which is a desired fact. For structural characterization of the material we used X-Ray Diffraction (XRD). The X-ray diffraction pattern for all samples indicates peaks which are agreeable with standard diffraction pattern of SnO2. The particle size of all samples was in the range of 28-92 nm calculated according to Scherrer equation.

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