Structural and luminescent properties of BaFe12−xAlxO19 compounds

The crystal structure and luminescent properties of Al-substituted [Formula: see text] were studied. It was found that under normal conditions, the samples are characterized by the space group P63/mmc. Depending on the ionic radii of the Al and Fe atoms and the concentration of Al atoms, a decrease in the distance between the atoms in the crystal structure and the lattice parameters was observed. [Formula: see text] crystals ([Formula: see text] = 0.1–1.2) were excited by a laser with a wavelength of 375 nm and 435 nm, to study their luminescent features. From the information obtained from luminescent spectrum, it is seen that with the replacement of magnetic [Formula: see text] ions by diamagnetic [Formula: see text] ions, the intensity of the spectra increases. During exciting by a laser with a wavelength of 435 nm, anti-Stokes luminescence is observed in the ultraviolet region.

Biotechnological method of obtaining nanoparticles of silver, cadmium and zinc sulfides. Physico-chemical characteristics. Creation of polymeric nanocomposites

A simple and environmentally safe method for obtaining stable nanoparticles of metal sulfides nanoparticles – NpAg2S, NpCdS and NpZnS was developed using different strains of microorganisms in an aqueous solution of metal salts and sulfur sources at the Research Center "Kurchatov Institute" – GosNIIgenetika. The concentration of nanoparticles is 1–4 mg/ml in aqueous suspensions. Using of the methods of electron microscopy, spectrofluorimetry, dynamic light scattering determined the main characteristics of biogenic nanoparticles: shape, size distribution, crystal structure, effective diameter, luminescent spectrum, zeta potential. According to its characteristics, these nanoparticles are referred to quantum dots. It is established that the stability of nanoparticles in aqueous suspensions is due to protein molecules adsorbed on the surface of nanoparticles, which are supplied by cells of microorganisms. Effective immobilization of biogenic nanoparticles on the surface of various polymer supports has been carried out. Biogenic nanoparticles along with nanoparticles obtained by physico-chemical methods can be used as fluorophores for imaging of biological processes, also as photocatalysts, solar cells and for new nanocomposite materials.

Fabrication and Optical Properties of 2at.%Yb:LuYAG Mixed Crystal through Nanocrystalline Powders

Ytterbium doped Lu1.5Y1.5Al5O12 (LuYAG) nanocrystalline powders were synthesized by a wet chemical mixed precipitant co-precipitation (MPP) method, and then the mixed crystal of Yb:LuYAG was grown in an optical floating zone (OFZ) furnace at the speed of 6–10 mm/h, using a [111] oriented YAG seed crystal. The transmittance of the polished LuYAG crystal is close to the ideal value of LuAG or YAG. The X-ray rocking curve shows complete symmetry and the full width at half maximum (FWHM) is 10 arc-second, indicating the good quality of as grown Yb:LuYAG multicomponent garnet crystal. The thermal luminescent spectrum at room temperature shows four deep energy traps at around 1–1.3 eV. X-ray excited luminesce (XEL) spectra is measured to characterize the existence of LuAl or YAl shadow defects in the bulk single crystal. The emission peak at around 320 nm indicates that the LuYAG crystal prepared by OFZ have lower concentrations of antisite defects (AD) with respect to its Czochralski counterpart.

Synthesis, Crystal Structure, Catalytic Properties, and Luminescent of a Novel Eu(III) Complex Material with 4-Imidazolecarboxaldehyde-pyridine-2-carbohydrazone

A novel Eu(III) complex, [Eu(L)2(H2O)4]·(NO3)·(H2O)4 (1) (H2L = 4-imidazolecarboxaldehyde-pyridine-2-carbohydrazide), was synthesized. Its structure has been characterized by elemental analysis, IR, and X-ray single crystal diffraction analysis. Complex 1 is of orthorhombic, space group Fdd2 with a = 29.471(6) A˚, b = 10.287(2) A˚, c = 24.340(5) A˚, V = 7379(3) A˚3, Z = 8, Mr = 902.58, Dc = 1.625 µg·m-3, µ = 1.789 mm-1, F(000) = 3656, GOOF = 1.099, the final R= 0.0517, ωR= 0.1292 for 3043 observed reflections with I > 2σ(I). The A3 coupling reaction has been investigated using the complex 1 as catalyst. The luminescent spectrum of the complex 1 gives two weak peaks (448 nm and 491 nm) and two strong peaks (596 nm and 620 nm) from excitation at 279 nm. Copyright © 2017 BCREC Group. All rights reserved.Received: 11st November 2016; Revised: 10th February 2017; Accepted: 23rd February 2017How to Cite: Wang, L.H., Liang, L., Li, P.F. (2017). Synthesis, Crystal Structure, Catalytic Properties, and Luminescent of a Novel Eu(III) Complex Material with 4-Imidazolecarboxaldehyde-pyridine-2-carbohydrazone. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2): 185-190 (doi:10.9767/bcrec.12.2.764.185-190)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.764.185-190

Synthesis, Characterization and Optical Property of KLaF4:Ce3+ Nano Particle

Ce3+doped cubic KLaF4system was synthesized by co-precipitation method. The sample was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectrophotometer and fluorescence spectrophotometer. The result indicated the nanoparticle diameter of KLaF4:Ce3+was 12.5 nm. The KLaF4:Ce3+had a stronger absorption at 250 nm, which could be explained by d elecronic transition of Ce3+. The maximum emission peak of KLaF4:Ce3+was 355 nm in its luminescent spectrum, and emission band of Ce3+also belonged to 5d→4f transition.

Luminescent and Photocatalytic Properties of BaCoF4: Ce3+ Synthesized by Reflux Method

The complex fluorides BaCoF4and BaCoF4: Ce3+were synthesized by reflux method in ethylene glycol and characterized by means of XRD, TEM, XPS, UV-VIS and Fluorescence Spectrophotometer. In addition, the photocatalytic degradation property of BaCoF4: Ce3+was investigated. The results indicated that the mean particle diameter of BaCoF4was 54.6 nm. Only adsorption oxygen (α oxygen) existed on the surface of BaCoF4and the content of surface oxygen was 5%. The BaCoF4: Ce3+had a stronger absorption at 250 nm, which could be explained by d electronic transition of Ce3+. The maximum emission peak of BaCoF4: Ce3+was 361.8 nm in its luminescent spectrum, and emission band of Ce3+belonged to 5d4f transition. Meanwhile, the degradation rate of acid red 3B by BaCoF4: Ce3+reached 98.7% after being lightened for 2 h by a 450 W high pressure mercury lamp.

Synthesis, Characterization and Fluorescent Properties of Complex Fluoride BaNiF4: Ce3+

The complex fluoride BaNiF4:Ce3+ was synthesized by reflux method using ethylene glycol as reaction solvent at its boiling point temperature. The sample was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and fluorescence spectrophotometer. The results indicated that the mean particle diameter of BaNiF4:Ce3+ was 53.8 nm. Only adsorption oxygen (α oxygen) existed on the surface of BaNiF4: Ce3+ and the content of surface oxygen was ≤5%. The maximum emission peak of BaNiF4:Ce3+ was 350 nm in its luminescent spectrum, and emission band of Ce3+ belonged to 5d→4f transition.

Yttrium Oxide Luminescence Films Preparated by Electrodeposition- Sinter Method

Luminescence film material plays a very important role in display technology. In this paper, electrochemical deposition of luminescent Y2O3:Eu or Y2O3:Tb thin films on transparent conducting optically ITO glass substrates by cathodes reduction of yttrium nitric was investigated. Y(OH)3 deposits were obtained using a conventional three electrode cell that potential of work electrode was –1.2v vs. Ag/AgCl electrode for 400 s in a 0.1mol/L Y(NO)3 with 4%(mol/mol) Eu(NO)3 at 65°C.Then this glass was sintered for 2h at 500°C.The luminescence spectrum of the film prepared by this method was tested. Its luminescent spectrum is the same as that of powder which prepared by solid method. Its XRD confirmed the formation of Y2O3 and SEM revealed uniformity of film.

Laboratory Simulation of Lunar Luminescence

Work has recently begun in the Physics Department of the Manchester College of Science and Technology on an attempt to simulate lunar luminescence in the laboratory. This programme is running parallel with that of our colleagues in the Manchester University Astronomy Department, who are making observations of the luminescent spectrum of the Moon itself. Our instruments are as yet only partly completed, but we will describe briefly what they are to consist of, in the hope that we may benefit from the comments of others in the same field, and arrange to co-ordinate our work with theirs.