scholarly journals Characterization of GAGG Doped with Extremely Low Levels of Chromium and Exhibiting Exceptional Intensity of Emission in NIR Region

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 673
Author(s):  
Greta Inkrataite ◽  
Gerardas Laurinavicius ◽  
David Enseling ◽  
Aleksej Zarkov ◽  
Thomas Jüstel ◽  
...  
Keyword(s):  
Sol Gel ◽  
X Ray Diffraction ◽  
Cubic Symmetry ◽  
Chromium Ions ◽  
3D Space ◽  
Main Observation ◽  
Gel Technique ◽  
Low Levels ◽  
Ppm Level

Cerium and chromium co-doped gadolinium aluminum gallium garnets were prepared using sol-gel technique. These compounds potentially can be applied for NIR-LED construction, horticulture and theranostics. Additionally, magnesium and calcium ions were also incorporated into the structure. X-ray diffraction data analysis confirmed the all-cubic symmetry with an Ia-3d space group, which is appropriate for garnet-type materials. From the characterization of the luminescence properties, it was confirmed that both chromium and cerium emissions could be incorporated. Cerium luminescence was detected under 450 nm excitation, while for chromium emission, 270 nm excitation was used. The emission of chromium ions was exceptionally intense, although it was determined that these compounds are doped only by parts per million of Cr3+ ions. Typically, the emission maxima of chromium ions are located around 650–750 nm in garnet systems. However, in this case, the emission maximum for chromium is measured to be around 790 nm, caused by re-absorption of Cr3+ ions. The main observation of this study is that the switchable emission wavelength in a compound of single phase was obtained, despite the fact that doping with Cr ions was performed in ppm level, causing an intense emission in NIR region.

Preparation and Characterization of Zn-Containing Hydroxyapatite/TiO2 Composite Coatings on Ti Alloys

2011 ◽  
Vol 685 ◽  
pp. 367-370 ◽  
Author(s):  
Min Qi ◽  
Da Yi Yang ◽  
Jing Ying Zhang ◽  
Hong Jun Ai
Keyword(s):  
Adhesion Strength ◽  
Composite Coatings ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Zn Content ◽  
Micro Arc Oxidation ◽  
Gel Technique ◽  
Bacteria Resistance

In order to improve the osteoblast growth and bacteria resistance, Zn-containing hydroxyapatite (Zn-HA) and titanium oxide (TiO2) composite coatings were prepared to improve binding between coating and Ti substrate. TiO2 film was prepared on the surface of Ti by micro-arc oxidation (MAO) and Zn-HA coating was deposited on TiO2 using sol–gel technique. Phase structure, composition and microstructure of the surface coatings were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS), respectively. The adhesion strength between the coatings with different Zn content was measured by tensile testing. The results showed that there was no significant influence of Zn content on adhesion strength between coating and Ti substrate.

Characterization of SrBi2Nb2O9 Thin Films Prepared by Sol Gel Technique

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Gel Technique ◽  
High Degree ◽  
First Time

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thicknesses of 0.1, 0.2, and 0.4 μ were grown by Sol-gel technique on silicon, and annealed at 650°C. The SBN films were investigated by Raman scatering for the first time. Raman spectra in some of the samples present bands around 60, 167, 196, 222, 302, 451, 560, 771, 837, and 863 cm−1, which correspond to the SBN formation. The study indicates that the films are inhomogeneous, and only in samples with thicknesses 0.4 μ the SBN material was found in some places. The prominent Raman band around 870 cm−1, which is the A1g mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift in different places in the same sample, as well as from sample to sample. The frequency shifts and the width of the Raman bands are discussed in term of ions in non-equilibrium positions. FT-IR spectra reveal a sharp peak at 1260 cm−1, and two broad bands around 995 and 772 cm−1. The bandwidths of the latter two bands are believed to be associated with the presence of a high degree of defects in the films. The experimental results of the SBN films are compared with those obtained in SBT (T=Ta) films. X-ray diffraction and SEM techniques are also used for the structural characterization.

Phase transformation and characterization of TiO2 and ZrO2 addition in the Li2O–Al2O3-SiO2 gels

1996 ◽  
Vol 11 (10) ◽  
pp. 2611-2615 ◽  
Author(s):  
Ming-Hong Lin ◽  
Moo-Chin Wang
Keyword(s):  
Phase Transformation ◽  
Sol Gel ◽  
Peak Position ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Ceramic Powders ◽  
Higher Temperature ◽  
Gel Technique ◽  
Dta Curves

Glass-ceramic powders with a composition of Li2O · Al2O3 · 4SiO2 (LAS) have been synthesized by the sol-gel technique using LiOCH3, Al(OC2H5)3, Si(OC2H5)4, Ti(OC2H5)4, and Zr(OC2H5)4 as starting materials and the phase transformation behavior during calcination has been investigated. Differential thermal analysis (DTA), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were utilized to determine the thermal behavior of the gels. Considering the LAS gels with 6.0 wt. % TiO2 and various wt. % ZrO2 content, and peak position of the β-spodumene phase formation in DTA curves was shifted to a higher temperature when the ZrO2 content was increased. The activation energy of β-spodumene crystallization was 283.8 kcal/mol for LAS gels with 6.0 wt. % TiO2 and 2.0 wt. % ZrO2. Unlike foregoing studies for LAS gels, during calcination of the dried LASTZ gels from 800 °C to 1200 °C neither β-eucryptite nor γ-spodumene was noted to be present. The crystallized phases comprised of β-spodumenes as the major phase and rutile (TiO2) together with zirconia (ZrO2) are precipitated as minor phases.

Thick PLZT Films Grown by Sol-gel for Optical Device Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
M. Linnik ◽  
O. Wilson ◽  
A. Christou
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Phase Modulator ◽  
X Ray Diffraction ◽  
X Ray ◽  
Device Applications ◽  
Gel Technique ◽  
Scanning Electron

AbstractThe preparation and characterization of thick PLZT films for spatial phase modulator applications are reported. Films were fabricated on LSCO/LAO substrates by a sol-gel technique using multiple heat-treatment parameters. The crystal quality of PLZT 9/65/35 films was investigated by X-ray diffraction and scanning electron microscopy.

Synthesis and Characterization of CeO2 Doped ZrO2 Ceramics by a Simple Sol-Gel Route

2017 ◽  
Vol 907 ◽  
pp. 56-60
Author(s):  
Ummuhanı Hilal Özer ◽  
Kerim Emre Öksüz ◽  
Ali Özer
Keyword(s):  
Tetragonal Phase ◽  
Sol Gel ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Zirconia Ceramics ◽  
Simple Method ◽  
X Ray ◽  
Gel Technique

It is well known that sol-gel technique is a simple method to produce nano sized ceramic powders. In this study, cerium oxide doped zirconia samples, with 10 mol%-12mol% and14mol% CeO2, were synthesized by sol-gel technique and characterized. The surface morphology, elemental composition, microstructure, and phase analysis, of the sintered CeO2 doped ZrO2 ceramics were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDS) analysis, and X-ray diffraction (XRD) respectively. X-ray diffraction for samples sintered at 1550 °C for 4h revealed that the zirconia ceramics have a tetragonal phase structure. The addition of CeO2 can raise the content of the tetragonal phase, but the minor monoclinic phase exists even at the CeO2 content of 10 mol%. The effect of dopant concentration on the lattice parameter, average primary crystallite size and micro-strain was studied. Relative densities for CeO2 doped ZrO2 bulk ceramics varied between 95% and 99 %, depending on the CeO2 addition.

scholarly journals Synthesis and Characterizations of LaMnO3 Perovskite Powders Using Sol-Gel Method 

2021 ◽  
Author(s):  
Deniz ÇOBAN ÖZKAN ◽  
Ahmet Türk ◽  
Erdal Celik
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Dye Sensitized Solar Cells ◽  
Ammonium Hydroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Sensitized ◽  
Gel Technique ◽  
Sensitized Solar Cells

Abstract The present research demonstrates the synthesis and characterization of LaMnO3 perovskite powders using the sol-gel technique for dye-sensitive solar cell applications. With this respect, transparent solutions were prepared from La and Mn based precursors, distilled water and citric acid monohydrate. Ammonium hydroxide was incorporated into the La-Mn solution in order to neutralize/precipitate at 24oC for 1 hour in the air. The solution was allowed to evaporate on a hot plate device at 90 °C in the air. The obtained solutions were dried at 90 oC for 24 hours to form a xerogel structure, dried at 200 oC for 2 hours and consequently annealed at 500 and 850 oC for 2 hours in the air. Thermal, structural, microstructural, optical and magnetic properties of the powders were characterized through differential thermal analysis-thermogravimetry (DTA-TG), Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM), Malvern zeta sizer (PSD), UV-vis spectrometer and vibrating sample magnetometer (VSM). The obtained results indicate promise, especially the low band range, that LaMnO3 powders can be used in dye-sensitized solar cells and can positively affect performance and efficiency.

Characterization of Sol-Gel Derived (Pb,Ba)(Zr,Ti,Nb)O3 Thin Films for Optical Waveguide Development

1994 ◽  
Vol 343 ◽  
Author(s):  
P. F. Baude ◽  
J. S. Wright ◽  
C. Ye ◽  
L. F. Francis ◽  
D. L. Polla
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Solution Preparation ◽  
Transmission Measurements ◽  
Gel Technique

ABSTRACT(PbBa)(ZrTiNb)03 thin films and powders have been prepared using the sol-gel technique. Solutions were synthesized in 2-methoxyethanol based upon our previous PZT solution preparation. Three different approaches were used for incorporating barium into PZT alkoxide solutions. Thermal analysis and x-ray diffraction results indicated that barium methoxypropoxide gave the best results. PBZTN (71% Pb and 71% Zr) was deposited onto sapphire substrates as well as oxidized silicon substrates. Optical transmission measurements showed greater than 80% transmission for wavelengths longer than 400 nm. Films with thickness of 3000 Å on sapphire exhibited a refractive index of 2.19 at λ=633 nm.

"Synthesis and characterization of Ba0.8Sr0.2TiO3 perovskite thin films prepared by Sol Gel Technique "

2020 ◽  
Vol 7 (2) ◽  
pp. 1-11
Author(s):  
Hamed A. Gatea ◽  
Iqbal Nahi
Keyword(s):  
Thin Films ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Perovskite Structure ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Barium Strontium ◽  
Intermediate Phases ◽  
Gel Technique

"Barium strontium Titanate (BST) is a solid solution consist of BaTiO3 and SrTiO3 that mixed with suitable ratio. Barium strontium Titanate oxide (Ba0.8Sr0.2TiO3) thin films prepared by sol gel technique. Barium strontium Titanate thin films deposited on Si substrate and annealed at [400,500, 600 and 700] ºC. The characterization of BST films investigated by a different technique, the X-Ray Diffraction (XRD) and Scanning Electron Macroscopy (SEM) revealed the phases, crystal structure and surface topography of the films. XRD pattern shows tetragonal phase for Ba0.8Sr0.2TiO3 perovskite structure with many peaks for different plans. The films annealed at the different temperature that indicated intermediate phases on perovskite structure of Ba0.8Sr0.2TiO3.

Synthesis and Characterization of Ba0.3Sr0.7ZrO3 Ceramic Thick Films Prepared by Sol-Gel Technique

2012 ◽  
Vol 620 ◽  
pp. 435-439 ◽  
Author(s):  
Wan Fahmin Faiz Wan Ali ◽  
Mohamad Ariff Othman ◽  
Nik Akmar Rejab ◽  
Mohd Zaid Abdullah ◽  
Arjuna Marzuki ◽  
...  
Keyword(s):  
Thick Films ◽  
Sol Gel ◽  
Dendritic Structure ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Electrical Permittivity ◽  
Electrical Characterizations

This manuscript is explained and discussed the properties of ceramic thick films, [Ba0.3Sr0.7ZrO3,BSZ (0.7)] synthesized through sol-gel route. The gel decomposition was studied by thermogravinometry analysis (TGA). From thermal analysis, it had shown that BSZ (0.7) phase started formed at 800 °C and above. The crystal structure of this composite film studied exhibited highly polycrystalline materials by X-ray diffraction analysis. From high magnification observation of field emission scanning electron microscopy (FESEM), grain boundaries of BSZ (0.7) films are clearly defined meanwhile grains displayed are in flaky shape. The average diameters of the grains measured were 94.6 nm. However, grains boundaries of BSZ (0.0) films, are unclear and grains slightly look dendritic structure. Electrical characterizations of the films are carried out with impedance analyzer at 4 - 12 GHz respectively. Both of electrical permittivity and loss tangent observed are dependable with microstructural and structural of the films.

scholarly journals Preparation and Characterization of Nickel Ferrite-SiO2/Ag Core/Shell Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
I. G. Blanco-Esqueda ◽  
G. Ortega-Zarzosa ◽  
J. R. Martínez ◽  
A. L. Guerrero
Keyword(s):  
Silver Nanoparticles ◽  
Nickel Ferrite ◽  
Sol Gel ◽  
Ferrite Nanoparticles ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Magnetic Composites ◽  
Nickel Ferrite Nanoparticles ◽  
Gel Technique

Magnetic composites with silver nanoparticles bonded to their surface were successfully prepared using a simple chemical method. By means of a sol-gel technique, nickel ferrite nanoparticles have been prepared and coated with silica to control and avoid their magnetic agglomeration. The structural and magnetic properties of the nanoparticles were studied in function of the annealing temperature. Then, silver nanoparticles were incorporated by hydrolysis-condensation of tetraethyl orthosilicate, which contains silver nitrate on the surface of the nickel ferrite-SiO2core/shell. Samples were characterized using X-ray diffraction, IR spectroscopy, SEM, and magnetometry. Results show that the silica covered the nickel ferrite nanoparticles and the silver nanoparticles remain stable in the surface of the composite.

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