scholarly journals Рентгенолюминесценция тетраподов ZnO, выращенных в присутствии примеси Сu и Au в исходной шихте

2020 ◽  
Vol 128 (11) ◽  
pp. 1652
Author(s):  
И.Д. Веневцев ◽  
А.Э. Муслимов ◽  
Л.А. Задорожная ◽  
А.С. Лавриков ◽  
П.А. Родный ◽  
...  
Keyword(s):  
Luminescence Spectrum ◽  
Luminescence Band ◽  
Broad Band ◽  
Luminescent Properties ◽  
Decay Kinetics ◽  
Weak Band ◽  
X Ray ◽  
Carbothermal Synthesis ◽  
Integrated Intensity ◽  
Band Edge Luminescence

The morphology and luminescent properties of ZnO tetrapod powders with Cu and Au impurities obtained by pyrolytic carbothermal synthesis were studied. The X-ray luminescence spectrum of the samples is dominated by a broad band in the range from 450 to 650 nm. A weak band-edge luminescence band with a maximum at 391 nm is also registered. Measurements of the decay kinetics showed the presence of both fast (~ 1 ns) and slow (~ 850 ns) luminescence components, where the fast one generally did not exceed 1% of the integrated intensity. It is shown that with the used doping method, the incorporation of Cu and Au impurities into the ZnO lattice does not occur. In this case, the presence of Cu with a concentration of up to 9% does not affect the morphology and luminescent properties of tetrapods, while Au has an effect even at a concentration close to 1%.

Effects of Charge Compensators on Structure and Luminescent Properties of Microwave Synthesized CaMoO4:Eu3+ Red Phosphors

2017 ◽  
Vol 727 ◽  
pp. 592-597
Author(s):  
Ying Han ◽  
Zhi Lin Li ◽  
Wan Zhang ◽  
Yan Jie Yin ◽  
Yan Mei Li ◽  
...  
Keyword(s):  
Broad Band ◽  
Luminescent Properties ◽  
Emission Peak ◽  
Luminous Intensity ◽  
Main Peak ◽  
Doping Amount ◽  
X Ray ◽  
Red Phosphors ◽  
Charge Compensator ◽  
Pure Phase

Red phosphors CaMoO4:Eu3+ were synthesized by microwave method with MnO2 as microwave absorbent. The phase structure and luminescent properties of the as-synthesized phosphors were investigated by X-ray powder diffraction and Fluorescence spectrophotometer. The results show that when the reaction time was 40 min, microwave power was medium-high fire (~560 W), we got the tetragonal CaMoO4:Eu3+ pure phase. The excitation spectrum of CaMoO4:Eu3+ was composed by a broad band between 200 nm and 350 nm and a series of peaks from 350 nm to 500 nm. The main peak was at 305 nm. The emission spectrum was composed of a series of peaks in the range of 550~750 nm and the main peak was at 617 nm due to the 5D0→7F2 transition of Eu3+. Doping charge compensator Li+, Na+ or K+ could improve the luminous intensity of the sample. When the doping amount of Li+, Na+ or K+ were 8 mol%, the luminous intensity of the sample reached the maximum. The intensity of the emission peak at 617 nm was 4.04, 3.42, 3.48 times of sample without doping charge compensator.

Synthesis and Luminescent Properties of Eu3+ Doped CaGd4O7 Phosphors by Solvothermal Reaction Method

2015 ◽  
Vol 15 (10) ◽  
pp. 8028-8033 ◽  
Author(s):  
Yeon Woo Seo ◽  
Mi Noh ◽  
Byung Kee Moon ◽  
Jung Hyun Jeong ◽  
Hyun Kyoung Yang ◽  
...  
Keyword(s):  
Broad Band ◽  
Luminescent Properties ◽  
Solvothermal Reaction ◽  
Sem Images ◽  
Reaction Method ◽  
X Ray ◽  
Chromaticity Coordinates ◽  
Potential Applications ◽  
Xrd Patterns ◽  
Cie Chromaticity

Eu3+ doped CaGd4O7 phosphors have been newly synthesized using a solvothermal reaction method and sintered at 1400 °C. The phase, composition, morphologies, and photoluminescent properties of the phosphors have been well characterized by means of the X-ray diffraction (XRD) patterns, energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectroscopy, and decay curves, respectively. The XRD patterns of the as-prepared phosphors confirm their monoclinic structure and the FE-SEM images reveal flower-like morphology, formed through agglomeration. The calculated size of the crystallites was approximately 83 nm. The photoluminescence excitation (PLE) spectra of CaGd4O7: Eu3+ phosphors consist of a broad band due to the charge transfer (CT) electronic transition, and several sharp peaks that can be attributed to the f–f transitions of Eu3+ and Gd3+. The PL spectra exhibited a stronger red emission corresponding to the 5D0→7F2 transition. The CIE chromaticity coordinates of the phosphors were calculated and all the chromaticity coordinates have been placed in the red spectral region. These luminescent powders are expected to have potential applications for white light-emitting diodes (WLEDs) and optical display systems.

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).

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

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

scholarly journals Structural and Enhanced Optical Properties of Stabilized γ‒Bi2O3 Nanoparticles: Effect of Oxygen Ion Vacancies

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1023 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Chia-Liang Cheng ◽  
Sheng Yun Wu
Keyword(s):  
Room Temperature ◽  
Excess Oxygen ◽  
Ambient Atmosphere ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Band Emission ◽  
Oxygen Ion ◽  
Integrated Intensity ◽  
Effect Of Oxygen

We report the synthesis of room temperature (RT) stabilized γ–Bi2O3 nanoparticles (NPs) at the expense of metallic Bi NPs through annealing in an ambient atmosphere. RT stability of the metastable γ–Bi2O3 NPs is confirmed using synchrotron radiation powder X-ray diffraction and Raman spectroscopy. γ–Bi2O3 NPs exhibited a strong red-band emission peaking at ~701 nm, covering 81% integrated intensity of photoluminescence spectra. Our findings suggest that the RT stabilization and enhanced red-band emission of γ‒Bi2O3 is mediated by excess oxygen ion vacancies generated at the octahedral O(2) sites during the annealing process.

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...

Luminescent Properties of Zn2SiO4:Eu3+,Dy3+ Phosphors via Sol-Gel Process

2012 ◽  
Vol 217-219 ◽  
pp. 733-736
Author(s):  
Xiu Mei Han ◽  
Shu Ai Hao ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectra ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir

Zn2SiO4:Eu3+, Dy3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1000oC. In Zn2SiO4:Eu3+,Dy3+ phosphors, the Eu3+ and Dy3+ show their characteristic red(613nm, 5D0-7F2), blue (481nm, 4F9/2–6H15/2) and yellow (577nm, 4F9/2–6H13/2) emissions.

Quantitative Study of Al/W Interaction In Si/SiO2/W-Ti/Al Thin Film System

1988 ◽  
Vol 119 ◽  
Author(s):  
Hung-Yu Liu ◽  
Peng-Heng Chang ◽  
Jim Bohlman ◽  
Hun-Lian Tsai
Keyword(s):  
Thin Film ◽  
Film System ◽  
X Ray Diffraction ◽  
Compound Formation ◽  
X Ray ◽  
Thin Film System ◽  
Glancing Angle ◽  
Integrated Intensity ◽  
Al Thin Film ◽  
Kinetics Of

AbstractThe interaction of Al and W in the Si/SiO2/W-Ti/Al thin film system is studied quantitatively by glancing angle x-ray diffraction. The formation of Al-W compounds due to annealing is monitored by the variation of the integrated intensity from a few x-ray diffraction peaks of the corresponding compounds. The annealing was conducted at 400°C, 450°C and 500°C from 1 hour to 300 hours. The kinetics of compound formation is determined using x-ray diffraction data and verified by TEM observations. We will also show the correlation of the compound formation to the change of the electrical properties of these films.

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