scholarly journals From Structure to Luminescent Properties of B2O3-Bi2O3-SrF2 Glass and Glass-Ceramics Doped with Eu3+ Ions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4490
Author(s):  
Karolina Milewska ◽  
Michał Maciejewski ◽  
Anna Synak ◽  
Marcin Łapiński ◽  
Aleksandra Mielewczyk-Gryń ◽  
...  
Keyword(s):  
Luminescence Intensity ◽  
Photoelectron Spectroscopy ◽  
Glass Ceramics ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Strontium Fluoride ◽  
Light Emitting ◽  
X Ray ◽  
The Fourier Transform

Glass-ceramics with the composition B2O3-Bi2O3-SrF2 were synthesized by the conventional melt-quenching technique and subsequent crystallization of the parental glasses. The temperature at which the ceramization was carried out was selected based on differential scanning calorimetry (DSC) analysis. The structure of the studied materials and the formation of SrF2 nanocrystals were confirmed by the Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. It was found that the amount of strontium fluoride introduced into the parental borate-bismuth glass has a significant impact on the growth of SrF2 nanocrystals. In particular, the influence of the crystalline SrF2 phase on luminescence intensity and kinetics was studied using Eu2O3-doped samples. An increase in luminescence intensity was observed in the samples in which SrF2 nanocrystals were formed. This is most likely related to the fact that some of the Eu3+ ions were (after annealing of the glass) located in the crystalline structure of strontium fluoride. This was confirmed both by the luminescence lifetime obtained based on the luminescence decay curves and the calculated Judd–Ofelt parameters, Ω2 and Ω4. The results achieved confirm that the glasses and glass-ceramics described in this work could be considered as a new phosphor for light-emitting diodes (LEDs).

scholarly journals Effect of the Degree of Substitution on the Hydrophobicity, Crystallinity, and Thermal Properties of Lauroylated Amaranth Starch

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2548
Author(s):  
Vicente Espinosa-Solis ◽  
Yunia Verónica García-Tejeda ◽  
Everth Jimena Leal-Castañeda ◽  
Víctor Barrera-Figueroa
Keyword(s):  
Photoelectron Spectroscopy ◽  
Thermal Characterization ◽  
Fatty Acyl ◽  
Degree Of Substitution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Amaranthus Hypochondriacus ◽  
Two Samples ◽  
Acyl Chains

In this paper, we consider amaranth starch extracted from the seeds of Amaranthus hypochondriacus L. An amphiphilic character is conferred to the starch by a chemical modification, which involves an esterification by lauroyl chloride at three modification levels. The degree of substitution (DS) after the modification ranged from 0.06 to 1.16. X-ray photoelectron spectroscopy analysis confirmed the presence of fatty acyl chains on the surface of the esterified starches. The hydrophobicity of starches was confirmed by their adsorption isotherms, which showed a decrease in the moisture adsorption of lauroylated as DS increased. X-ray diffraction analysis revealed a higher crystallinity, which was observed in the two samples subjected to the highest levels of modification. A higher crystallinity is related to a higher gelatinization enthalpy. These results are in agreement with the thermal characterization obtained by differential scanning calorimetry (DSC). An inhibition of the retrogradation properties of lauroylated amaranth starches was also observed.

scholarly journals Effects of Impurity Doping on the Luminescence Performance of Mn4+-Doped Aluminates with the Magnetoplumbite-Type Structure for Plant Cultivation

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 86 ◽  
Author(s):  
Xiaoshuang Li ◽  
Zikun Chen ◽  
Bo Wang ◽  
Ruizhao Liang ◽  
Yongting Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Light Emitting Diode ◽  
Octahedral Complex ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
Light Emitting ◽  
X Ray ◽  
Color Changes ◽  
Plant Cultivation ◽  
Impurity Doping

Mn4+ activated LaMgAl11O19 (LMA/Mn4+) with red emitting phosphor was obtained by sintering under air conditioning. The X-ray diffraction pattern Rietveld refinement results reveal that three six-fold coordinated Al sites are substituted by Mn4+ ions. Furthermore, the chemical valence state of manganese in the LMA host was further confirmed through X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Photoluminescence emission (PL) and excitation (PLE) spectra of LMA/Mn4+ as well as the lifetime were measured, and the 663 nm emission is ascribed to the 2Eg→4A2g from the 3d3 electrons in the [MnO6]8− octahedral complex. The emission spectrum matches well with the absorption of phytochrome. Temperature-dependent PL spectra show that the color changes of the phosphor at 420 K are 0.0110 for Δx and −0.0109 for Δy. Moreover, doping Zn2+ and Mg2+ ions in the host enhances the emission intensity of Mn4+ ions. These results highlight the potential of LMA/Mn4+ phosphor for a light-emitting diode (LED) plant lamp.

STUDIES ON SURFACE STRUCTURE, MORPHOLOGY AND COMPOSITION OF Co–W COATINGS ELECTRODEPOSITED WITH DIRECT AND PULSE CURRENT USING GLUCONATE BATH

2013 ◽  
Vol 20 (01) ◽  
pp. 1350006 ◽  
Author(s):  
PARTHASARATHI BERA ◽  
H. SEENIVASAN ◽  
K. S. RAJAM
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pulse Current ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Force Microscopy ◽  
Dsc Studies ◽  
Atomic Force ◽  
Electrodeposited Coating

Co–W alloy coatings were deposited with direct current (DC) and pulse current (PC) electrodeposition methods using gluconate bath at pH5 and characterized by X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). DSC studies hint at the possibility of formation of metallic glasses. Detailed XPS studies of these alloy coatings have been carried out to compare elemental states and composition of Co and W in DC and PC electrodeposited alloys. DC-plated alloy has significant amount of Co and W metal along with their respective oxidized species. In contrast, mainly oxidized metals are present in the following layers of as-deposited coatings prepared with PC plating. Concentration of Co metal is observed to increase during sputtering, whereas there is no change in W6+ concentration. Microhardness measurement of all the Co–W coatings shows higher hardness compared to Co metal and 1:1 and 1:4 PC electrodeposited coatings show little higher hardness compared to 1:2 PC electrodeposited coating.

scholarly journals Preparation and study of the luminescent glass-ceramics based on barium iodide activated with Eu2+

2019 ◽  
pp. 38-44
Author(s):  
Tatsiana A. Salamakha ◽  
Ekaterina E. Trusova ◽  
Yauhen U. Tratsiak
Keyword(s):  
Water Vapor ◽  
Diffraction Analysis ◽  
Glass Ceramics ◽  
Luminescent Properties ◽  
Original Method ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Iodide ◽  
Spectral Luminescent Properties

In this paper an original method for obtaining glass-ceramics based on barium iodide powder activated with Eu2+ is proposed, their structural and spectral-luminescent properties are investigated. X-ray diffraction analysis has evidenced that glass-ceramics containing BaI2 ∙ 2H2O and BaI2 are formed when 50 mas. % of the starting iodide powder is used in the synthesis process. The possibility of using glass-ceramics for preventing the contact of iodide powder with water vapor has been confirmed.

Atomic layer deposition of HfO2, Al2O3, and HfAlOx using O3 and metal(diethylamino) precursors

2007 ◽  
Vol 22 (12) ◽  
pp. 3455-3464 ◽  
Author(s):  
Rajesh Katamreddy ◽  
Ronald Inman ◽  
Gregory Jursich ◽  
Axel Soulet ◽  
Christos Takoudis
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Thermal Characteristics ◽  
Atomic Layer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Metal Precursors ◽  
Layer Deposition ◽  
Xrd Techniques

Tetrakis-diethylamino hafnium (TDEAH), tris-diethylamino aluminum (TDEAA), and ozone were used for the atomic layer deposition (ALD) of HfO2, Al2O3, and HfAlOx films. The ALD rates were measured to be 1.1 Å/cycle for HfO2 and 1.3 Å/cycle for Al2O3. The ALD temperature windows were found to be between 200 and 325 °C for TDEAA, and between 200 and 275 °C for TDEAH. The overlap of these ALD windows between 200 and 275 °C is critical for ALD of the composite film, HfAlOx. In addition to the overlapping ALD temperature windows, the two metal precursors have similar thermal characteristics, as shown by TGA and differential scanning calorimetry. As-deposited films and films postannealed at 600 and 800 °C films were analyzed using Fourier transformed infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffraction (XRD) techniques. FTIR spectra revealed interfacial oxide growth during deposition of both HfO2 and Al2O3 whose thickness increased with annealing temperature. The FTIR data also indicated hydroxyl and nitrate groups in the films; these species were removed after annealing in Ar at a temperature of ⩾600 °C. Both FTIR and XRD results indicated the crystallization of pure HfO2 after annealing at temperatures as low as 600 °C. On the other hand, pure Al2O3 remained amorphous after annealing at temperatures up to 800 °C. XRD data of the composite HfAlOx film show that films deposited by alternating five cycles of HfO2 and one cycle of Al2O3 remained amorphous after annealing at 600 °C. Rutherford backscattering analysis of HfAlOx deposited with a varied number of alternating HfO2 and Al2O3 cycles demonstrated a strong correlation between the cyclic dosage of TDEAA and TDEAH and the film composition.

Simplified Synthesis and Luminous Mechanism of Eu2+-Doped α-Si3N4 Nanowires with Strong Green Luminescent Properties

2017 ◽  
Vol 727 ◽  
pp. 635-641 ◽  
Author(s):  
Rui Su ◽  
Zhi Feng Huang ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Broad Band ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broad Band Emission ◽  
Band Emission ◽  
Nitridation Process ◽  
Transmission Electron

Ultra-long, single crystal, Eu-doped α-Si3N4 nanowires were prepared by a simple approach involving nitriding Eu-doped cryomilled nanocrystalline Si powder in NH3 flow at 1350 °C for 4 h. Phases, chemical composition and microcosmic feature of cryomilled powders and as-prepared nanowires were tested by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), respectively. The results suggested that Eu was successfully introduced into Si lattice after the cryomilling process and then entered into the lattice of α-Si3N4 during the nitridation process. The as-synthesized Eu-doped α-Si3N4 nanowires had highly uniform dimension with 20~30 nm in diameter and ~100 μm in length. The room temperature photoluminescence (PL) spectrum of as-synthesized nanowires showed a broad band emission center at 570 nm which was attributed to the transition from 4f65d to 4f7 in Eu2+. The transition from Eu3+ to Eu2+ during nitridation process was tested by X-ray photoelectron spectroscopy (XPS).

Preparation and Characterization of Transparent Oxyfluoride Tellurite Glass-Ceramics Containing CaF2 Nanocrystals

2014 ◽  
Vol 989-994 ◽  
pp. 305-307
Author(s):  
Zhao Xia Hou ◽  
Hang Xin Li ◽  
Shao Hong Wang ◽  
Mei Han Wang ◽  
Xiao Dan Hu
Keyword(s):  
Tellurite Glass ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melting Method ◽  
X Ray ◽  
Average Size ◽  
Scanning Electron ◽  
Temperature Melting

Transparent oxyfluoride tellurite glass-ceramics containing CaF2 nanocrystals were prepared by high temperature melting method. The glass-ceramics were characterized by Differential scanning calorimetry, X-ray diffraction and scanning electron microscope, respectively. The results showed that the CaF2 nanocrystals were spherical and the average size was found to be 60 nm.

Preparation and characterization of 1,2,4,5-benzenetetra carboxylic-chitosan

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Nurhidayatullaili Muhd Julkapli ◽  
Zulkifli Ahmad ◽  
Hazizan Md Akil
Keyword(s):  
Xrd Analysis ◽  
Absorption Capacity ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
H Nmr ◽  
Crystalline Nature ◽  
The Fourier Transform

AbstractChemically cross-linked chitosan (MC) containing 1,2,4,5- benzenetetracarboxylic acid (BCA) as the cross-linking agent was prepared to improve the metal ions absorption capacity of native chitosan (NC) and limit its biodegradability. The Fourier transform infra-red (FTIR) and proton neutron magnetic resonance (1H NMR) results showed that BCA was successfully linked onto N-position of NC. The crystalline nature of NC was reduced significantly after cross-linking as examined by X-ray diffraction (XRD) analysis. Therefore, the glass transition temperature (Tg) of MC was higher than NC as reported by differential scanning calorimetry (DSC). Moreover, thermogravimetric (TGA) analysis showed that, MC had better thermal stability than NC. Morphology changes on the surface of NC and MC were characterized by field emission scanning electron microscopy (FESEM) and showed that MC had more porous surface than NC. In pH medium of 3 to 6, MC had excellent Cu (II) ions absorption capacity with a maximum 16 % higher than NC.

Synthesis of Oriented BiFeO3 Thin Films by Chemical Solution Deposition: Phase, Texture, and Microstructural Development

2005 ◽  
Vol 20 (8) ◽  
pp. 2127-2139 ◽  
Author(s):  
F. Tyholdt ◽  
S. Jørgensen ◽  
H. Fjellvåg ◽  
A.E. Gunnæs
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Chemical Solution Deposition ◽  
Microstructural Development ◽  
Chemical Solution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Solution Deposition ◽  
X Ray ◽  
Glass Substrates

Textured, thin films of BiFeO3 (∼120 nm thickness) were synthesized by chemical solution deposition from a mixture of iron- and bismuth- 2-methoxyethoxides on Si(100)/SiO2/TiO2/Pt substrates. The use of alkoxides ensured good homogeneity and a low degree of organics that further facilitated low crystallization temperatures. Crystalline films were according to x-ray diffraction already obtained at 480 °C. Precursor characteristics were investigated using thermogravimetry and differential scanning calorimetry, whereas phase purity, microstructure and film topography were examined by x-ray diffraction, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. A small (10%) Bi excess was found necessary to obtain dense, pore-free films. Such additions also prevented decomposition of BiFeO3 at high temperatures. The observed (012) texture is believed to originate from the growth mechanism as no relation to the substrate is found. This is also confirmed by observing (012) texture for films on glass substrates.

Glass-Ceramics Obtained from Sewage Sludge and its Characteristics Affected by Alkalinity

2014 ◽  
Vol 937 ◽  
pp. 70-73
Author(s):  
Di Wu ◽  
Jun Zhang ◽  
Xing Wang Wen ◽  
Hui Ling Liu
Keyword(s):  
Sewage Sludge ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sludge Disposal ◽  
Physical And Chemical ◽  
And Chemical Properties

Sewage sludge was tested as component for producing glass-ceramics with the addition of analytic reagent CaO to solve the sewage sludge disposal problems. The effect of alkalinity (Ak=mCaO/mSiO2) on the characteristics of the glass-ceramics was investigated. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to investigate thermal behavior and crystalline phase of the samples. It was found that the degree and characteristics of crystals in vitrified sludge significantly correlate to the alkalinity of the raw materials. The glass-ceramics with Ak = 0.36 possessed the best physical and chemical properties.

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