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.

scholarly journals Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Low Frequency ◽  
Solid State Reaction Method ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Frequency Regime ◽  
Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

scholarly journals Synthesis of Na-Doped Lithium Metatitanate and Its Absorption for Carbon Dioxide

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Liu Zhirong ◽  
Zhang Huan ◽  
Wang Yun ◽  
Zhan Xinxing
Keyword(s):  
Carbon Dioxide ◽  
Solid State Reaction Method ◽  
Absorption Capacity ◽  
Absorption Kinetics ◽  
X Ray Diffraction ◽  
Carbon Dioxide Absorption ◽  
Reaction Method ◽  
X Ray ◽  
Xrd Patterns ◽  
The Relationship

Na-doped lithium metatitanate (Na-doped Li2TiO3) absorbent was doped with Na2CO3and lithium metatitanate (Li2TiO3) was prepared by a solid-state reaction method from mixture of TiO2and Li2CO3. The Na-doped lithium metatitanate was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and surface area. Carbon dioxide absorption on Na-doped lithium metatitanate was investigated using TG-DTA. The results reveal an increase of the CO2absorption capacity of the Na-doped materials with respect to pure Li2TiO3. XRD patterns of the doped samples suggest a limited substitution of Li by Na atoms within the Li2TiO3structure. The results of experimental and modeling work were summarized to better understand the relationship between the sorbent microstructure and carbon dioxide absorption kinetics.

Synthesis and upconversion luminescence properties of CaF2:Yb3+,Er3+ nanoparticles obtained from SBA-15 template

2010 ◽  
Vol 25 (10) ◽  
pp. 2035-2041 ◽  
Author(s):  
Zhiguo Xia ◽  
Peng Du
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Average Diameter ◽  
Cubic Phase ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Transmission Electron

CaF2:Yb3+,Er3+ upconversion (UC) luminescence nanoparticles have been synthesized using mesoporous silica (SBA-15) as a hard template. The samples were characterized by x-ray diffraction, Fourier transform infrared spectra, field-emission scanning electron microscopy, transmission electron microscopy, and UC emission spectra, respectively. Highly crystalline cubic phase CaF2:Yb3+,Er3+ nanoparticles are uniformly distributed with an average diameter of about 40–50 nm, and the formation process is also demonstrated. The UC fluorescence has been realized in the as-prepared CaF2:Yb3+,Er3+ nanoparticles on 980-nm excitation. The UC emission transitions for 4F9/2–4I15/2 (red), 2H11/2–4I15/2 (green), 4S3/2–4I15/2 (green), and 2H9/2–4I15/2 (violet) in the Yb3+/Er3+ codoped CaF2 nanoparticles depending on pumping power and temperature have been discussed. The UC mechanism, especially the origin on the temperature-dependent UC emission intensities ratio between 2H11/2 and 4S3/2 levels, have been proposed.

Photoluminescence of Eu3+-Doped La2Mo2O9 Phosphors

2010 ◽  
Vol 663-665 ◽  
pp. 332-335
Author(s):  
En Guo Wang
Keyword(s):  
Sintering Temperature ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Doping Amount ◽  
Obvious Effect ◽  
Reaction Method ◽  
X Ray ◽  
Europium Ion ◽  
Scanning Electron

Eu3+-doped La2Mo2O9 phosphor was fabricated by sold-state reaction method. The as-prepared samples were characterized by the application of X-ray diffraction (XRD), scanning electron microscopy (SEM), and emission spectra. The effect of the sintering temperature and doping amount of europium ion on the luminescent properties of La2Mo2O9:Eu3+ was investigated. The results show that the luminescent intensity will reach the strongest when the sintering temperature is equal to 1073 K. The Eu3+ doping amounts also have obvious effect on the luminescent properties.

MULTIFERROIC MATERIALS Bi1-xSmxFeO3: A STUDY OF RAMAN AND ABSORPTION SPECTROSCOPIES

2010 ◽  
Vol 19 (02) ◽  
pp. 247-254 ◽  
Author(s):  
NGUYEN VAN MINH ◽  
DAO VIET THANG
Keyword(s):  
Lattice Dynamics ◽  
Optical Band Gap ◽  
Solid State Reaction Method ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Lattice Constants ◽  
Raman Measurement

Multiferroic Bi 1-x Sm x FeO 3(x = 0.00, 0.05, 0.1, 0.15, 0.2) ceramics were prepared by conventional solid state reaction method. X-ray diffraction measurement was carried out to characterize the crystal structure and to detect the impurities existing in these ceramics. The substitution of rare earth Sm for Bi was found to decrease the impurity phase in BiFeO 3 ceramics. There is strong evidence that both lattice constants a and c of the unit cell become smaller as the Sm 3+ content is increased. The effect of introducing Sm 3+ is shown to decrease the optical band gap for doped sample Bi 1-x Sm x FeO 3. Additionally, the temperature-dependent Raman measurement performed for the lattice dynamics study of Bi 1-x Sm x FeO 3 samples reveals a strong band centered at around 1000–1300 cm-1 which is associated with the resonant enhancement of two-phonon Raman scattering in the multiferroic Bi 1-x Sm x FeO 3 samples. This two-phonon signal is shown to broaden with increasing x. The Raman spectra at low wavenumbers are suggested to be related with magnon in this system.

Effect of Different Excitation Wavelengths on Luminescent Properties of ZnO/Anodic Alumina Membrane (AAM) Arrays

2018 ◽  
Vol 10 (3) ◽  
pp. 409-412
Author(s):  
Shihua Zhao
Keyword(s):  
Emission Spectra ◽  
Luminescent Properties ◽  
Anodic Alumina ◽  
Anodic Alumina Membrane ◽  
X Ray Diffraction ◽  
Alumina Membrane ◽  
Sem Images ◽  
Diffraction Peaks ◽  
Lattice Planes ◽  
Xrd Patterns

ZnO/AAM (anodic alumina membrane) arrays were prepared by an electrodeposition method and X-ray diffraction (XRD) patterns show that the characteristic diffraction peaks of ZnO appear, such as the lattice planes of (100), (002), and (102), moreover, the diffraction peaks of Al2O3 are dominated. Scanning electron microscopy (SEM) images show that the average sizes of the ZnO particles are about 100 nm corresponding to the channel diameters of AAM, and the ZnO arrays are composed of those close particles linked together. The photoluminescence emission spectra express that the as-prepared ZnO arrays can give out relatively pure ultraviolet light (395 nm) from the excitons.

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.

Influence of Eu2+ Doped Contents on the Spectroscopic Features of Sr2-X MgSi2O7:xEu2+

2012 ◽  
Vol 476-478 ◽  
pp. 1232-1236
Author(s):  
Jia Zhe Guo ◽  
Ya Dong Li ◽  
Yan Lin Huang
Keyword(s):  
Emission Spectra ◽  
Optical Excitation ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Broad Absorption ◽  
Broad Absorption Band ◽  
Phase Purity ◽  
Reaction Method ◽  
X Ray ◽  
Uv Led

Silicate-based Sr2-xMgSi2O7:xEu2+(x=0.01, 0.03, 0.05, 0.07) phosphors were synthesized by the high temperature solid-state reaction method. Phase purity and crystal structure of the phosphors were characterized using X-ray diffraction spectrometer. The optical excitation and emission spectra of Eu2+ ion were measured using luminescence spectrometer and fluorescence spectrophotometer. The emission spectra showed a strong blue luminescence peaked around 470 nm, corresponds to the 4f65d1 →4f7 transition on Eu2+. Two different average decay time confirmed that the Eu2+ cations may occupy in two different lattice sites and presents different spectroscopic features. With a broad absorption band extending from 224 to 450 nm, it is suggestive that the phosphors have a potential application in UV-LED chips (360-400 nm).

Hollow Spherical CaMoO4:Eu3+, Li+ Phosphors Prepared by Spray Pyrolysis

2013 ◽  
Vol 652-654 ◽  
pp. 563-566
Author(s):  
Xia Wang ◽  
Chang Cheng Liu ◽  
Zhen Hua Liang ◽  
Gui Hua Peng ◽  
Xiao Bao Han
Keyword(s):  
Spray Pyrolysis ◽  
Hollow Spheres ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Spray Pyrolysis Method ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Red Phosphors ◽  
Diffraction Peaks

Hollow spherical CaMoO4:Eu3+, Li+red phosphors have been successfully synthesized by spray pyrolysis method. The crystalline phase, morphology and luminescent properties of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence emission spectra (PL). The XRD results demonstrated that all the diffraction peaks of the samples can be well indexed to the tetragonal phase of CaMoO4. The SEM images showed that the particles were composed of hollow spheres, whose diameters are about 1.4 μm. The as-prepared CaMoO4:Eu3+, Li+hollow spheres show a strong red emission corresponding to the5D0-7F2transition of the Eu3+ ions under ultraviolet light.

Synthesis and Optical Properties of Eu3+ Doped NaYF4 and KYF4 Micro/Nanocrystals

2016 ◽  
Vol 16 (4) ◽  
pp. 3857-3860 ◽  
Author(s):  
Siling Guo ◽  
Chunyan Cao ◽  
Renping Cao
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Local Environment ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Two Samples ◽  
Xrd Patterns ◽  
The Eu

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.

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