Study of Luminescent Properties of CaNb2O6:Yb, Er, Tm

2020 ◽  
pp. 78-87
Author(s):  
E.A. Moskvitina ◽  
V.A. Vorobiev ◽  
B.M. Bolotin
Keyword(s):  
Luminescence Spectrum ◽  
Solid Phase ◽  
Luminescent Properties ◽  
Luminescence Spectra ◽  
Energy Transfer Mechanism ◽  
X Ray ◽  
Luminescence Efficiency ◽  
Intermediate Phases ◽  
Diffraction Patterns ◽  
Calcium Niobate

We used solid phase synthesis at 1200 °C to create a luminophore based on CaNb2O6 and activated by ytterbium, erbium, and thulium ions. We present X-ray phase analysis results for the CaNb2O6:Yb, Er, Tm compound. The X-ray diffraction patterns obtained do not contain reflexes belonging to the intermediate phases. We investigated spectral properties of a calcium niobate-based luminophore upon excitation by a 940 nm laser. There are bands in the visible and IR regions to be found in the luminescence spectra. The up-conversion (anti-Stokes emission) luminescence spectrum comprises three bands peaking at 560, 676 and 807 nm. In the IR range, there are three peaks to be detected in the luminescence spectrum at 1010, 1540 and 1812 nm. We established the luminescence variation patterns for compounds based on CaNb2O6:Yb, Er, Tm. We determined the optimum Tm3+ concentration in the system that makes it possible to achieve the highest luminescence efficiency in the 1640--2000 nm range peaking at 1812 nm. We considered an energy transfer mechanism involving Yb3+ and Er3+ as luminescence stabilisers in a thulium ion. Employing erbium as an additional sensitiser allowed the luminescence intensity in the 1812 nm band to be increased by 1.5 time

Synthesis and properties of double gadolinium tellurites

2021 ◽  
Vol 103 (3) ◽  
pp. 67-73
Author(s):  
A.A. Toibek ◽  
◽  
K.T. Rustembekov ◽  
D.A. Kaikenov ◽  
M. Stoev ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Solid Phase ◽  
Heat Capacities ◽  
Ceramic Technology ◽  
Phase Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Temperature Range ◽  
Diffraction Patterns

For the first time, double gadolinium tellurites of the composition GdMIITeO4.5 (MII — Sr, Ba) were synthesized by the solid-phase method. The solid-phase synthesis of samples was carried out from decrepitated gadolinium (III) and tellurium (IV) oxides, strontium, and barium carbonates according to the standard ceramic technology. The synthesis was carried out in the temperature range of 800-1100 °C. The samples obtained were confirmed by X-ray phase analysis. X-ray phase analysis was carried out on an Empyrean instrument in the XRDML Pananalitical format. The intensity of the diffraction maxima was estimated on a 100-point scale. X-ray diffraction patterns indexing of the powder of gadolinium tellurites — alkaline earth metals studied were carried out by the homology method. The reliability and correctness of the results of indexing the X-ray diffraction patterns are confirmed by the good agreement between the experimental and calculated values of the interplanar distances (d) and the agreement between the values of the X-ray and pycnometric densities. It was found that compounds GdSrTeO4.5 and GdBaTeO4.5 crystallize in the monoclinic system and have the unit cell parameters, namely GdSrTeO4.5 — a = 12.7610, b = 10.4289, c = 8.6235 Å, V° = 1141.83 Å3, β = 95.77°, Z = 5, ρrent. = 3.22, ρpikn. = (3.10±0.09) g/cm3; GdBaTeO4.5 — a = 15.7272, b = 15.8351, c = 7.1393 Å, V° = 1769.72 Å3, β = 95.53°, Z = 8, ρrent = 3.71, ρpick = (3.61±0.10) g/cm3. Using the Landiya method, the standard heat capacities of the compounds were estimated from the calculated values of the standard entropies, and the temperature dependences of the heat capacities of the gadolinium tellurites synthesized were determined in the temperature range of 298–850 K.

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.

scholarly journals Interlayer Structure of Bioactive Molecule, 2-Aminoethanesulfonate, Intercalated into Calcium-Containing Layered Double Hydroxides

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Tae-Hyun Kim ◽  
Hyoung Jun Kim ◽  
Jae-Min Oh
Keyword(s):  
Layered Double Hydroxides ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Cation ◽  
Particle Size And Morphology ◽  
Interlayer Structure ◽  
Diffraction Patterns ◽  
Size And Morphology ◽  
Double Hydroxides

We have successfully intercalated 2-aminoethanesulfonate, a well-known biomolecule taurine, into calcium-containing layered double hydroxides via optimized solid phase intercalation. According to X-ray diffraction patterns and infrared spectroscopy, it was revealed that the intercalated taurine molecules were each directly coordinated to other calcium cation and arranged in a zig-zag pattern. Scanning electron microscopy showed that the particle size and morphology of the LDHs were not affected by the solid phase intercalation, and the surface of intercalates was covered by organic moieties. From ninhydrin amine detection tests, we confirmed that most of the taurine molecules were well stabilized between the calcium-containing LDH layers.

Preparation of Exfoliated Polyethylene/Clay Nanocomposites at High Clay Content

2010 ◽  
Vol 150-151 ◽  
pp. 561-564
Author(s):  
Hao Qun Hong ◽  
Hai Yan Zhang ◽  
Hui He ◽  
De Min Jia
Keyword(s):  
Solid Phase ◽  
Clay Content ◽  
Layered Silicates ◽  
Clay Nanocomposites ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
High Polarity

The polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by melt blending the organic MMT with the ternary-monomer graft copolymers of polyethylene (GPE) which were prepared by solid phase grafting maleic anhydride, methyl methacrylate and butyl acrylate onto PE. Fourier transform infrared spectroscopy was used to characterize the structure of GPE. X-ray diffraction patterns and transmission electron microscopy were used to characterize the morphology of GPE/MMT nanocomposites. Results showed that GPE was an outstanding polymeric material to prepare an exfoliated polymer/layered silicates nanocomposites due to the high polarity of GPE and high graft degree. Most layered silicates still maintain the exfoliated and well dispersed state even at 40 phr OMMT content. The exfoliation of layered silicates was attributed to the well intercalation and easy wetting of the grafted oligomers.

One-Step Synthesis and Luminescent Properties of Nanocrystalline YVO4:Eu3+ Powders

2008 ◽  
Vol 8 (3) ◽  
pp. 1228-1233 ◽  
Author(s):  
Deyan Kong ◽  
Zhenling Wang ◽  
Cuikun Lin ◽  
Piaoping Yang ◽  
Zewei Quan ◽  
...  
Keyword(s):  
Bulk Material ◽  
Luminescent Properties ◽  
Photoelectron Spectra ◽  
Synthesis Process ◽  
Luminescence Spectra ◽  
Luminescence Decay Curve ◽  
Xps Spectra ◽  
X Ray ◽  
Temperature Solution ◽  
Ft Ir

In this paper, nanocrystalline YVO4:Eu3+ powders have been successfully synthesized via high-temperature solution-phase synthesis process. The nanocrystalline YVO4:Eu3+ particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV/Vis absorption spectra and luminescence spectra, luminescence decay curve and Fourier transform infrared (FT-IR), X-ray photoelectron spectra (XPS) respectively. The as-prepared nanocrystalline YVO4:Eu3+ particles are well crystallized with ellipsoidal morphology. The emission of YVO4:Eu3+ particles show emission originating from the 5D0 level, with 5D0–7F2 at 616 nm as the most prominent group. The excitation spectrumfits basically with the absorption spectrumfromthe vanadate ions. FT-IR and XPS spectra indicate that the surface ligands of nanocrystalline particles were oleic acid and oleylamine. The lifetime for the luminescence of Eu3+ in the as-prepared YVO4:Eu3+ samples are shorter than that of the bulk material due to the absorption of organic ligands on the nanoparticle surface.

scholarly journals Effect of sulfur on the scintillation properties of mixed ZnSxSe1–x crystals

2018 ◽  
pp. 36-42
Author(s):  
O. G. Trubaieva ◽  
M. A. Chaika ◽  
O. V. Zelenskaya ◽  
A. I. Lalayants ◽  
S. N. Galkin
Keyword(s):  
Directional Solidification ◽  
Sulfur Content ◽  
Light Output ◽  
Luminescent Properties ◽  
High Energy ◽  
Luminescence Spectra ◽  
Bulk Crystals ◽  
X Ray ◽  
Basic Properties ◽  
Better Than

ZnSxSe1–x based luminescent materials are promising for use as X-ray and g-ray detectors. The main advantage of ZnSxSe1–x crystals is the possibility of making of solid solutions over an entire X-range. It was found that varying the composition of ZnSxSe1–x crystals can change their luminescent properties. Many studies were focused on obtaining ZnSxSe1–x mixed crystals, most using a vapour phase growth methods, and only some of works used the directional solidification. The directional solidification techniques allow growing large ZnSxSe1–x crystals for high-energy particles detectors. Practical use, however, requires the knowledge about luminescent properties of ZnSxSe1–x bulk crystals. This study reports the effect of sulfur content on basic properties of ZnSxSe1–xx bulk crystals grown by Bridgman-Stockbarger method. Six different compounds were studied: ZnS0.07Se0.93, ZnS0.15Se0.85, ZnS0.22Se0.78, ZnS0.28Se0.72, ZnS0.32Se0.68, ZnS0.39Se0.61. The ZnSe(Al) and ZnSe(Te) crystals grown at the similar conditions were used as reference. X-ray luminescence was studied using РЕИС-И (REIS-I) X-ray source (Cu, U = 10—45 kV). КСВУ-23 (KSVU-23) spectrophotometer was used to analyse the emission spectra. The afterglow level h(%) was determined by Smiths Heimann AMS-1 spectrophotometer at excitation by such X-ray and g-ray sources as 123Cs and 241Am (59.5 keV). Light output is one of the main characteristics of the scintillator, which determines its quality as a detector. The ZnSxSe1-x crystals demonstrated increase in the intensity of X-ray induced luminescence spectra with increasing of sulfur content and reached maximum for ZnS0.22Se0.78 composition. Light output of ZnSxSe1–x bulk crystals are higher than those of ZnSe(Te) and ZnSe(Al) commercial crystals. Moreover, thermal stability of scintillation light output of ZnSxSe1–x bulk crystals are also better than those. This investigation has revealed that basic properties of ZnSxSe1–x based scintillation detectors are better than those of ZnSe(Te) and ZnSe(Al).

Hydrothermal synthesis of micrometer doping CaWO4 phosphors assisted by polymerization

2016 ◽  
Vol 30 (19) ◽  
pp. 1650246
Author(s):  
Liyong Wang ◽  
Yuanyuan Han ◽  
Dan Wang ◽  
Shiqi Wang ◽  
Guoxin Lu ◽  
...  
Keyword(s):  
Phenol Formaldehyde ◽  
Luminescent Properties ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Lanthanide Ions ◽  
Structure Characteristic ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

CaWO4 crystals were prepared by hydrothermal method assisting with phenol-formaldehyde polymer. The morphology can be controlled by polymer, and X-ray diffraction patterns results present a scheelite-type tetragonal structure, characteristic infrared active modes for O–W–O in the range from 500 cm[Formula: see text] to 4000 cm[Formula: see text] by Fourier transform infrared spectroscopic techniques. Raman results indicate that the crystals possess seven Raman active modes in the range from 100 cm[Formula: see text] to 1000 cm[Formula: see text]. A scanning electron microscopy study reveals that the particles exhibit uniform morphology. Luminescent properties were investigated by photoluminescence measurements, multicolor phosphors were obtained when Ca[Formula: see text] was substituted partly by lanthanide ions.

Crystal Structure and Luminescent Properties of Complex [Eu0.5Gd0.5(C12H9O2)2(C12H8N2)2(H2O)2]•(C12H9O2)•H2O

2012 ◽  
Vol 554-556 ◽  
pp. 691-694
Author(s):  
Hai Tao Xia ◽  
Yu Fen Liu ◽  
De Fu Rong
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Ternary Complex ◽  
Luminescent Properties ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
Red Emission ◽  
X Ray ◽  
Sharp Band ◽  
Complex Display

One new rare-earth ternary complex with 1-naphthylacetic acid and 1,10-phenanthroline, [Eu0.5Gd0.5(C12H9O2)2(C12H8N2)2(H2O)2]•(C12H9O2)•H2O were synthesized. The structures were established by single crystal X-ray diffraction. The europium (gadolinium) ion is eight-coordinate with four oxygen and four nitrogen atoms forming a coordination polyhedron best describable as a distorted dodecahedral. The luminescence spectra of the complex in a solution of DMF were studied. The complex display characteristic Eu(III)-originated red emission as a sharp band at 617 nm. It is concluded that the metal-centered red emission is promoted by the ligand-assisted energy transfer.

Microstructure Formation of Al-Fe-Mn-Si Aluminides by Pressure-Assisted Reactive Sintering of Elemental Powder Mixtures

2009 ◽  
Vol 68 ◽  
pp. 21-33 ◽  
Author(s):  
Alfredo Flores ◽  
J.A. Toscano ◽  
S. Rodríguez ◽  
A. Salinas R. ◽  
Enrique Nava-Vázquez
Keyword(s):  
Microstructural Characterization ◽  
Rietveld Analysis ◽  
Reactive Sintering ◽  
X Ray Diffraction ◽  
Microstructure Formation ◽  
Powder Mixtures ◽  
X Ray ◽  
Intermediate Phases ◽  
Diffraction Patterns ◽  
Metallurgical Reactions

This paper presents the results of an investigation aimed at understanding microstructure formation of Al-Fe-Mn-Si intermetallics during pressure-assisted reactive sintering of elemental powders. The proportion of elements was selected such that the composition of the product was 55 wt % Al, 17 wt % Si, 14 wt % Mn, and 14 wt % Fe. Experiments were conducted at temperatures between 600 and 800°C, using compaction stresses of up to 20 MPa. Rietveld analysis of x-ray diffraction patterns of fully processed samples showed that the powders were transformed into a mixture of Al9FeMnSi and Al9FeMn2Si phases. However, as temperature and pressure were increased, the Al9FeMnSi phase was transformed into the Al9FeMn2Si phase. Differential Thermal Analysis, as well as microstructural characterization by scanning electron microscopy and x-ray diffraction, showed that these intermetallics do not form directly from the powder mixtures. Rather, they are the result of metallurgical reactions between a molten Al-Si solution and various intermediate phases formed during reactive sintering.

Luminescent Properties of As-Grown and Vacuum Annealed LiNbO3 Single Crystals

2013 ◽  
Vol 200 ◽  
pp. 199-202
Author(s):  
Dmytro Yu. Sugak ◽  
Andriy P. Luchechko
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Annealed Sample ◽  
Luminescence Spectra ◽  
Excitation Spectra ◽  
X Ray ◽  
Grown Sample ◽  
Different Types

This paper reports on the luminescent properties of the congruent as-grown and vacuum annealed LiNbO3 single crystals at the UV and X-ray excitations. The shape of excitation spectra is similar for all emission bands in as-grown sample as well as in vacuum annealed sample. The emission spectra (exc=235 nm) observed in the spectral region 250…800 nm at room temperature consist of five elementary bands. Correlation of the relative intensities bands in luminescence spectra under different types of excitation and their temperature dependencies were determined. The most intensitive maxima in as-grown sample are observed at 295 and 691 nm. The main maximum after vacuum annealing is peaked around 295 nm.

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