Effect of Trace Fe3+ on Luminescent Properties of CaWO4: Pr3+ Phosphors

2016 ◽  
Vol 71 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Ke Wang ◽  
Xu Feng ◽  
Wenlin Feng ◽  
Shasha Shi ◽  
Yao Li ◽  
...  
Keyword(s):  
Doping Concentration ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Transfers ◽  
Decay Times ◽  
Lifetime Testing ◽  
Testing Techniques ◽  
The Mean

AbstractFe3+ undoped and doped CaWO4: Pr3+ phosphors have been successfully synthesised by using the solid-state reaction method. The products were characterised by powder X-ray diffraction (XRD), photoluminescence (PL) and fluorescence lifetime testing techniques, respectively. The mean crystallite size (50.7 nm) of CaWO4: Pr3+ is obtained from powder XRD data. PL spectra of both Fe3+ undoped and doped CaWO4: Pr3+ phosphors exhibit excitation peaks at 214, 449, 474, and 487 nm under monitor wavelength at 651 nm, and emission peaks at 532, 558, 605, 621, 651, 691, 712, and 736 nm under blue light (λem=487 nm) excitation. The effect of trace Fe3+ on luminescence properties of CaWO4: Pr3+ phosphor is studied by controlling the doping concentration of Fe3+. The results show that radioactive energy transfers from luminescence centre Pr3+ to quenching centre Fe3+ occurred in Fe3+ doped CaWO4: Pr3+ phosphors. With the increasing concentration of Fe3+, the energy transfer from Pr3+ to Fe3+ is enhanced, and the emission intensity of CaWO4: Pr3+ will be lower. The decay times (5.22 and 4.99 μs) are obtained for typical samples Ca0.995WO4: Pr3+0.005 and Ca0.99275WO4: Pr3+0.005, Fe3+0.00225, respectively. This work shows that nonferrous phosphors can improve the luminescent intensity of the phosphors.

scholarly journals Luminescence, Energy Transfer, and Upconversion Mechanisms of Y2O3Nanomaterials Doped with Eu3+,Tb3+, Tm3+,Er3+, and Yb3+Ions

2007 ◽  
Vol 2007 ◽  
pp. 1-10 ◽  
Author(s):  
TranKim Anh ◽  
Paul Benalloul ◽  
Charles Barthou ◽  
Lam thiKieu Giang ◽  
Nguyen Vu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Doping Concentration ◽  
Spherical Shape ◽  
X Ray Diffraction ◽  
X Ray ◽  
Decay Times ◽  
Structure Phase ◽  
High Resolution Tem ◽  
Average Size ◽  
20 Nm

Luminescence, energy transfer, and upconversion mechanisms of nanophosphors (Y2O3 : Eu3+,Tb3+,Y2O3 : Tm3+,Y2O3 : Er3+,Yb3+) both in particle and colloidal forms were studied. The structure, phase, and morphology of the nanopowders and nanocolloidal media were determined by high-resolution TEM and X-ray diffraction. It was shown that the obtained nanoparticles have a round-spherical shape with average size in the range of 4 to 20 nm. Energy transfer was observed forY2O3 : Eu3+,Tb3+colloidal and powders, upconversion transitions were observed for bothY2O3 : Er3+andY2O3 : Er3+,Yb3+nanophosphors. The dependence of photoluminescence (PL) spectra and decay times on doping concentration has been investigated. The infrared to visible conversion of emission inY2O3 : Er3+,Yb3+system was analyzed and discussed aiming to be applied in the photonic technology.

Synthesis and Luminescent Properties of M2P2O7:Eu3+ (M = Ca, Sr, Ba ) Phosphors

2011 ◽  
Vol 399-401 ◽  
pp. 978-981
Author(s):  
Fu Wang Mo ◽  
Rong Fang Wang ◽  
Yu Wei Lan ◽  
Li Ya Zhou ◽  
Tao He ◽  
...  
Keyword(s):  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Microscopy Observation ◽  
Excitation Peak ◽  
Strong Emission ◽  
X Ray ◽  
Red Phosphors ◽  
Strong Excitation

A series of orange-red phosphors M2P2O7: Eu3+ (M = Ca, Sr, Ba ) were prepared by traditional solid-state reaction method. X-ray diffraction analysis confirmed the formation of Ca2P2O7, Sr2P2O7 and Ba2P2O7. Scanning electron-microscopy observation indicated a narrow size-distribution of about 0.6~1 μm for the particles with a quadrate shape. Photoluminescence spectra of M2P2O7(M = Ca, Sr, Ba ): Eu3+ phosphors showed a strong excitation peak around 393 nm, and Ca2P2O7: Eu3+, Sr2P2O7: Eu3+ and Ba2P2O7: Eu3+ phosphors showed strong emission bands peaking at about 593 nm, which suggests that the Eu3+ ion is occupy the site with center of symmetry.

scholarly journals Synthesis, Luminescent Properties and White LED Fabrication of Sm3+ Doped Lu2WMoO9

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 403
Author(s):  
Zijun Chen ◽  
Huiyi Xu ◽  
Chunyan Cao ◽  
Xiaoting Chen ◽  
Min Zhang ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
White Led ◽  
X Ray Diffraction ◽  
Nonradiative Relaxation ◽  
Temperature Dependent ◽  
X Ray ◽  
Xrd Patterns ◽  
Synthesized Materials

In this paper, Sm3+ doped Lu2W0.5Mo0.5O6, Lu2WMoO9, and Lu2(W0.5Mo0.5O4)3 materials were synthesized by using a two-step solid-state reaction method. The synthesized materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electronic micrograph (FE-SEM) pictures, photoluminescence (PL) excitation and emission spectra, and temperature-dependent emission intensities. Orange-reddish light could be observed from the phosphors under ultraviolet (UV) 365 nm light. The Sm3+ doped Lu2WMoO9 had enhanced PL intensities compared to the other two materials. The excitation, the energy transfer, the nonradiative relaxation, and the emission processes were illustrated by using schematic diagrams of Sm3+ in Lu2MoWO9. The optimal Sm3+ doping concentration was explored in the enhancing luminescence of Lu2WMoO9. By combing the Sm3+ doped Lu2WMoO9 to UV 365 nm chips, near white lighting emitting diode (W-LED) were obtained. The phosphor can be used in single phosphor-based UV W-LEDs.

Influences of Eu2+ and Dy3+ Contents on the Properties of Long Afterglow Strontium Aluminate Phosphors

2010 ◽  
Vol 62 ◽  
pp. 88-94 ◽  
Author(s):  
Selvin Yesilay Kaya ◽  
Bekir Karasu ◽  
Guray Kaya ◽  
Erkul Karacaoğlu
Keyword(s):  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Long Afterglow ◽  
Bluish Green ◽  
Molar Percent

The detailed preparation process of Eu2+ and Dy3+ ion co-doped phosphor powders in Sr4Al14O25:Eu2+/Dy3+ phosphor system with bluish-green long afterglow produced by solid state reaction method under reducing atmosphere is here reported. X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis were made to assign the effects of Eu and Dy ions on the luminescent properties of the synthesized phosphors, which were determined by measuring the photoluminescence spectra. The maximum emission intensity of these phosphors under excitation was investigated. As a result, the relevant values were obtained from the phosphorescent pigment with 0.21% and 0.05% molar percent of Eu2+ and Dy3+.

Studies of Microstructure and Electro-Magnetic Transport Property of La0.67Ca0.33MnO3 Ceramic

2017 ◽  
Vol 373 ◽  
pp. 205-208
Author(s):  
Shou Lei Xu ◽  
Er Juan Xie ◽  
Xiu Qing Cao ◽  
Yu Yang Huang ◽  
Ding Kang Xiong ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Positron Lifetime ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Metal Insulator ◽  
X Ray ◽  
Maximum Value ◽  
The Mean ◽  
Magnetic Transport ◽  
Electro Magnetic

The positron annihilation techniques and X-ray diffraction have been used to study the microstructure of the La0.67Ca0.33MnO3 ceramics prepared by the solid-state reaction method at different sintered temperatures (T=1573K, 1623K, 1673K, 1723K, 1773K, 1823K). And the electro-magnetic transport behavior of the samples was measured by VSM and Resistivity modular on PPMS. According to these results, all samples show a perovskite structure, the ferromagnetic-paramagnetic and metal-insulator transitions occur at the transition temperature Tc and TMI, respectively, which is almost the same. For La0.67Ca0.33MnO3 sintered at 1673K, the mean positron lifetime is the largest, the maximum value of the magnetization is achieved on the magnetization-temperature curve at H=0.2mT, while the transition temperature occurs at about 244K.

Near-Infrared Quantum Cutting in Yb3+ Doped SrMoO4 Phosphors

2016 ◽  
Vol 16 (4) ◽  
pp. 3494-3499 ◽  
Author(s):  
Xiaobing Luo ◽  
Jun Shen ◽  
He Huang ◽  
Lu Xu ◽  
Zhixiang Wang ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Good Crystallinity ◽  
Nir Emission ◽  
Quantum Cutting

Efficient near-infrared (NIR) quantum cutting (QC) has been demonstrated in Yb3+ doped SrMoO4 phosphors synthesized by the high-temperature solid-state reaction method. The obtained SrMoO4:Yb3+ phosphors were characterized by X-ray diffraction (XRD), diffuse reflectance spectra, photoluminescence (PL) spectra and decay lifetime to understand the observed near-infrared quantum cutting phenomena. The XRD results show that all the prepared phosphors can be readily indexed to the pure tetragonal phase of SrMoO4 and exhibit good crystallinity. The experimental results showed that the strong visible molybdate (MoO2−24 emission around 493 nm and near-infrared (NIR) emission around 1000 nm from Yb3+(2F5/2 → 2F7/2) of SrMoO4:Yb3+ phosphors were observed under ultraviolet (290 nm) excitation. The Yb3+ concentration dependence of luminescent properties and lifetimes of both the visible and NIR emissions have also been investigated. The quenching concentration of Yb3+ ions approaches as high as 10 mol%. The cooperative energy transfer (CET) mechanism was also discussed in detail. The broadband NIR QC phosphors may possibly have potential application in enhancing the conversion efficiency of solar cells.

scholarly journals Effect of Eu3+ doping concentration on the structural and luminescence properties of NaYF4: Eu3+ nanoparticles

2020 ◽  
Vol 5 (1) ◽  
pp. first
Author(s):  
Cao Thi My Dung ◽  
Tran Thi Thanh Van ◽  
Lê Thuy Thanh Giang
Keyword(s):  
Emission Intensity ◽  
Doping Concentration ◽  
Solvothermal Method ◽  
Luminescent Properties ◽  
Hexagonal Structure ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimal Doping Concentration ◽  
Xrd Patterns

In our study, hexagonal-NaYF4: Eu3+ nanoparticles were synthesized by the solvothermal method at 180◦C for 24 hours. The typical vibrational spectrum showed the appearance of characteristic organic modes of oleic acid in the sample. The presence of elements such as Na, Y, F and Eu was indicated in the energy-dispersive X-ray spectroscopy (EDX). X-ray diffraction (XRD) patterns revealed that the NaYF4 host possessed the hexagonal structure when the doping contents below 5 mol%. At the Eu3+ amount of 10 mol%, the XRD appeared additional peaks of cubic phase of NaYF4 host. Both XRD and TEM data showed that the crystal sizes increase slightly as a function of Eu3+ doping concentration. Under an excitation at 395 nm, photoluminescence (PL) spectra revealed that the ratio of emission intensity between orange and red were controlled by changing the doping concentration. The optimal doping concentration was about 7 mol% for achieving the highest emission intensity. Moreover, PL data also demonstrated that a part of ions Eu3+ could occupy at Y3+ sites in the crystal structure of NaYF4. Because of their outstanding luminescent properties, NaYF4:Eu nanoparticles would the potential material for applications in biomedical medicine, optoelectronics.

Luminescent Properties of Sr2B5O9Cl Phosphor Doped with Eu

2007 ◽  
Vol 336-338 ◽  
pp. 625-628 ◽  
Author(s):  
Na Su ◽  
Zi Long Tang ◽  
Zhong Tai Zhang
Keyword(s):  
Solid State ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
The Other ◽  
Luminescent Material ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Ultraviolet Excitation ◽  
High Efficient

Sr2B5O9Cl:Eu phosphor with high efficient luminescent material was synthesized by solid-state reaction method in air. The result of X-ray diffraction showed that the pure Sr2B5O9Cl phase forms at 900°C. The emission spectrum of Sr2B5O9Cl:Eu under 254nm excitation contained two parts. One part was constituted by a strong peak located at 417nm due to the d→f transition of Eu2+ ion, and the other part contained five weak peaks between 580-660nm due to the 5D0→7FJ(J=1,2,3) of Eu3+ ion. The infrared spectrum revealed that both BO3 unites and BO4 unites coexisted in the resultant product. The Eu2+ was surrounded and protected from being oxidized by the BO4 unites. Both red and blue visible lights were observed under ultraviolet excitation as a result of the coexistence of Eu2+ ion and Eu3+ ion.

Isomorphous replacement in electron diffraction of wet crystals of rat hemoglobin

1983 ◽  
Vol 41 ◽  
pp. 446-447
Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons
Keyword(s):  
Electron Diffraction ◽  
Heavy Atom ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Salt Solutions ◽  
X Ray ◽  
Isomorphous Replacement ◽  
Structure Factors ◽  
Diffraction Structure ◽  
The Mean

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.

Luminescent Properties of Gd2MoO6:Eu3+ Nanophosphor for WLEDs

2021 ◽  
Author(s):  
Yan Chen ◽  
Yuemei Lan ◽  
Dong Wang ◽  
Guoxing Zhang ◽  
Wenlong Peng ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Fluorescence Spectra ◽  
Solvothermal Method ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

A series of Gd2-xMoO6:xEu3+(x=0.18-0.38) nanophosphors were synthesized by the solvothermal method. The properties of this nanophosphor were characterized by x-ray diffraction (XRD), transmission electron microscope (TEM), fluorescence spectra and diffuse...

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