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.

X-ray diffraction study of oxygen-conducting compoundsLn2Mo2O9(Ln= La, Pr)

2014 ◽  
Vol 70 (4) ◽  
pp. 669-675 ◽  
Author(s):  
Alexander M. Antipin ◽  
Olga A. Alekseeva ◽  
Natalia I. Sorokina ◽  
Alexandra N. Kuskova ◽  
Michail Yu. Presniakov ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Ion Migration ◽  
Transmission Microscopy ◽  
Coordination Environment ◽  
X Ray ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Oxygen Ion Migration

The La2Mo2O9(LM) and Pr2Mo2O9(PM) single crystals are studied using precision X-ray diffraction and high-resolution transmission microscopy at room temperature. The crystal structures are determined in the space groupP213. La and Pr atoms, as well as Mo1 and O1 atoms, are located in the vicinity of the threefold axes rather than on the axes as in the high-temperature cubic phase. In both structures studied, the O2 and O3 positions are partially occupied. The coexistence of different configurations of the Mo coordination environment facilitates the oxygen-ion migration in the structure. Based on the X-ray data, the activation energies of O atoms are calculated and the migration paths of oxygen ions in the structures are analysed. The conductivity of PM crystals is close to that of LM crystals. The O2 and O3 atoms are the main contributors to the ion conductivity of LM and PM.

Study of the Phase Formation of Sol-Gel YBa2Cu3O7-x Samples in Flowing Oxygen Atmosphere

2007 ◽  
Vol 546-549 ◽  
pp. 2097-2102
Author(s):  
Ting Luo ◽  
Yi Zhang ◽  
Qing Rong Feng
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Oxygen Atmosphere ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Whole Process ◽  
Relationship Of ◽  
The Relationship ◽  
Flowing Oxygen

The relationship of the resistivity versus synthesizing temperature of sol-gel YBa2Cu3O7-x samples, with Tc 91K, was studied while synthesizing in flowing oxygen atmosphere. A set of high temperature -T curves were obtained for the whole process. After four rounds of synthesizing, the resistivity of the sample was =1.00×10-3cm at room temperature. The -T curve of the last round also showed that the orthorhombic to tetragonal phase transformation of the sample occurred around 600oC that is lower than the YBa2Cu3O7-x sample prepared in ambient atmosphere. Other measurements such as X-ray diffraction, SEM measurement, low temperature R-T and M-T measurement were also taken to get more information of these samples.

Photoluminescence and Structural Characteristics of SnO2 Nanopetals Synthesized by Thermal Evaporation

2010 ◽  
Vol 152-153 ◽  
pp. 697-701
Author(s):  
Bing Wang ◽  
Ling Li
Keyword(s):  
Room Temperature ◽  
Thermal Evaporation ◽  
Structural Characteristics ◽  
The Self ◽  
Silicon Substrates ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Sno2 Nanostructure

A new nanostructure, (2D) nanopetal of SnO2, has been grown on single silicon substrates by Au-Ag alloying catalyst assisted carbothermal evaporation of SnO2. Field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and Raman are employed to identify the morphology and structure of the synthesized productions. Room-temperature photoluminescence (PL) is used to characterize the luminescence of SnO2 nanostructure. Three new peaks at 356, 450 and 489 nm in the measured photoluminescence spectra are observed, implying that more luminescence centers exist in SnO2 nanopetals due to nanocrystals and defects. The growth of the SnO2 nanopetals is discussed on the basis of the self-catalyst mechanism.

Characterization of Nd:Y3Al5O12 Thin Films Prepared by Electron Beam Evaporation Deposition

2013 ◽  
Vol 320 ◽  
pp. 150-154
Author(s):  
Hao Ren ◽  
Qun Zeng ◽  
Xi Hui Liang
Keyword(s):  
Thin Films ◽  
Electron Beam ◽  
Room Temperature ◽  
Electron Beam Evaporation ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Morphologies ◽  
Ingaas Detector

Nd:YAG thin films have been prepared on Si (100) substrates by electron beam evaporation deposition. The surface morphologies, crystalline phases and optical properties of the Nd:YAG thin films were characterized by x-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, and spectrophotometer. The crystallization of Nd:YAG thin films was improved after annealing at 1100 °C for 1 hour in vacuum. Excited by a Ti:sapphire laser at 808 nm, photoluminescence spectra of Nd:YAG thin films were measured at room temperature, and the transition of4F3/24I11/2of Nd3+in YAG in the region of 1064 nm were detected by a liquid nitrogen cooled InGaAs detector array.

Growth, optical and EPR properties of Li1.72Na0.28Ge4O9 single crystals pure and slightly doped with Cr

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Anna Jasik ◽  
Marek Berkowski ◽  
Slawomir Kaczmarek ◽  
Andrzej Suchocki ◽  
Agata Kaminska ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ambient Atmosphere ◽  
Solid Solution Series ◽  
Photoluminescence Spectra ◽  
Czochralski Technique ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Band ◽  
Field Modulation

AbstractSingle crystals of lithium-sodium-tetragermanate, a member of the solid solution series Li2−xNaxGe4O9 with x=0.28, pure and slightly doped with Cr3+ ions (0.03 mol.% and 0.1 mol.%), were grown in ambient atmosphere by the Czochralski technique from stoichiometric melt. The crystals with dimensions up to 20 mm in diameter and 50 mm in length were obtained. The crystal structure has been determined by means of X-ray diffraction. Phase analysis and structural refinement of the Li1.72Na0.28Ge4O9 crystals were performed by X-ray powder diffraction using Ni-filtered Cu Kα radiation with a Siemens D5000 diffractometer. The absorption, excitation and photoluminescence spectra of the crystals were measured in the UV-VIS and IR range at low temperatures. EPR investigations were performed using a conventional X-band Bruker ELEXSYS E 500 CW-spectrometer operating at 9.5 GHz with 100 kHz magnetic field modulation. Temperature and angular dependences of the EPR spectra of the crystal samples were recorded in the 3–300 K temperature range.

X-Ray Diffraction Studies of Crystallization in Elastomers

1956 ◽  
Vol 29 (2) ◽  
pp. 438-450 ◽  
Author(s):  
Leroy E. Alexander ◽  
Stanley Ohlberg ◽  
G. Russell Taylor
Keyword(s):  
Natural Rubber ◽  
Molecular Orientation ◽  
Room Temperature ◽  
Geiger Counter ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Integrated Intensity ◽  
Beam Monitor

Abstract In general, extension of an elastomer results in a degree of preferred orientation of the molecular chains composing the amorphous phase. Therefore the amorphous fraction of a partially crystalline elastomer must be related to the integrated intensity of the amorphous diffraction halo rather than to the intensity at any one azimuth. A noteworthy exception is natural rubber, for which simple meridional measurements suffice. A Geiger-counter apparatus, with beam monitor and temperature-controlling accessories, is described for making accurate measurements of the x-ray intensities scattered at any azimuth and at small or moderate Bragg angles. Measurements of crystallinity in natural rubber are in essential agreement with the findings of previous workers. When polybutadiene is extended at room temperature, molecular orientation occurs, but little if any crystallization. Measurements at lowered temperatures show that the crystalline fraction becomes appreciable at about 0° C and that it increases with further reduction of temperature and with increasing extension ratio. Preferred orientation of the crystalline regions in extended polybutadiene has been measured quantitatively with the object of providing jointly with birefringence measurements a value of the birefringence of a single crystal of polybutadiene.

scholarly journals A Study of Structural and Photoluminescence for Al-Doped CdO Thin Films

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Bong Ju Lee ◽  
Jin Jeong
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Deposition Time ◽  
Processing Parameters ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
X Ray ◽  
Grain Sizes ◽  
Cdo Thin Films

Al-doped CdO thin films were prepared by radio frequency magnetron sputtering at different deposition time and substrate temperature. X-ray diffraction showed that the changes in the intensities of the (200), (220), and (311) planes followed a similar trend with increase in deposition time. The surface of the thin film was examined by scanning electron microscopy. Grain sizes of Al-doped CdO thin films increased significantly with increasing deposition time. The film thicknesses were 0.09, 0.12, 0.20, and 0.225 μm for the deposition times of 1, 2, 3, and 4 h, respectively. The photoluminescence spectra of the Al-doped CdO thin films were measured at room temperature. The photoluminescence wavelength changed in the sequence, green, blue, green, and blue, with increasing deposition time, which indicates that blue light emitting films can be fabricated by adjusting the processing parameters.

Spontaneous ferromagnetism at room temperature in oxygen-rich dicalcium cuprate Ca2CuO3+δ

1996 ◽  
Vol 11 (7) ◽  
pp. 1804-1809 ◽  
Author(s):  
Mahjoub A. Abdelgadir ◽  
Richard S. Burrows ◽  
Darl H. McDaniel
Keyword(s):  
Saturation Magnetization ◽  
Elemental Analysis ◽  
Applied Field ◽  
Room Temperature ◽  
Magnetic Impurity ◽  
Oxygen Depletion ◽  
Excess Oxygen ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar

Stoichiometric Ca2CuO3, having square-planar Cu-chains [C. L. Teske and H. Müller-Buschbaum, Z. Anorg. Allg. Chem. 379, 234 (1970); M. Hjorth and J. Hyldtoft, Acta Chem. Scand. 44, 516 (1990)], is expectedly antiferromagnetic due to 1D intrachain superexchange [K. Okuda, S. Noguchi, K. Konishi, H. Deguchi, and K. Takeda, J. Magn. Magn. Mater. 104–107, 817 (1992)]. Nonetheless, we report remarkable spontaneous ferromagnetism at 293 K after sintering, prominently in oxygen. This apparently introduced excess oxygen at vacant quasioctahedral sites, promoting spin-flip and ferromagnetic interchain coupling. Thermogravimetry (TGA) revealed excess oxygen, ≈0.17 O/Cu. X-ray diffraction (XRD) yielded a comparatively smaller unit cell. Ferromagnetism disappeared by oxygen depletion, mimicking reported nonmagnetism of Ca2CuO3−δ [Okuda et al. (1992)]. Elemental analysis showed insignificant magnetic impurity traces. Tc ranged between 680 K and 723 K, depending on freshness and purity. Saturation magnetization varied with processing, optimally 0.30 A · m2/kg at 1.0 T applied field. Coercivity and remanence varied with purity.

Preparation of CuS Hollow Microsphere by a Simple Hydrothermal Method and its Catalytic Property

2012 ◽  
Vol 535-537 ◽  
pp. 329-332 ◽  
Author(s):  
Ming Rui Wang ◽  
Wen Jiang Li ◽  
Mei Ling Pan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Hollow Microsphere ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Catalytic Material ◽  
Phase Pure ◽  
Scanning Electron

A simple method was applied to fabricate phase-pure hollow CuS microspheres. The obtained product was characterized by X-ray diffraction, scanning electron microscopy, photoluminescence spectra and UV-Vis absorption spectroscopy. Further, the catalytic activity of CuS spheres was evaluated by the decolorization of Rhodamine B in the presence of hydrogen peroxide solution at room temperature. The results indicated that the product showed a good optical propertie, and the hollow sphere CuS could be an effective catalytic material.

Preparation and Photoluminescence of In2O3 Nanofibers by Electrospinning

2011 ◽  
Vol 412 ◽  
pp. 49-52
Author(s):  
Ya Wei Hu ◽  
Hui Rong He ◽  
Yang Min Ma
Keyword(s):  
Room Temperature ◽  
Deep Level ◽  
Sol Gel ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Indium Nitrate ◽  
Gel Processing

Ultra-thin fibers of indium oxide (In2O3) were prepared by sol-gel processing and the electrospinning technique using polyvinylpyrrolidone (PVP) and indium nitrate as precursors. The fibers were characterized by the thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and room temperature photoluminescence spectra. It was observed that the In2O3 nanofibers exhibited photoluminescence peaks centered at 526 and 590 nm, corresponding to the defeat-related deep-level emission.

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