scholarly journals New amorphous nanophosphors obtained by evaporation of silicates and germanates REE

2017 ◽  
Vol 89 (10) ◽  
pp. 1505-1520
Author(s):  
Mikhail G. Zuev ◽  
Vladislav G. Il’ves ◽  
Sergey Yu. Sokovnin ◽  
Andrei A. Vasin ◽  
Elena Yu. Zhuravleva
Keyword(s):  
Electron Beam ◽  
Laser Excitation ◽  
Electron Beam Evaporation ◽  
Scanning Calorimetry ◽  
Radiation Reduction ◽  
Bulk State ◽  
Pulsed Electron Beam ◽  
First Time ◽  
Luminescence Characteristics ◽  
Raman And Ir Spectra

Abstract Amorphous nanophosphors have been produced by pulsed electron beam evaporation of bulk phosphors of rare earth elements (REE) silicates and germanates with oxyapatite structure activated with europium. The processes of crystallization of amorphous nanopowders (NP) have been studied by differential scanning calorimetry and thermogravimetry (40–1400°C) methods. A modification of the Raman and IR spectra of the samples was found when the particle size decreased from bulk to nanostate due to insignificant polymerization of Si(Ge)O4 tetrahedra. The spectral and luminescence characteristics of the bulk samples as well as nanoamorphous samples have been examined. It was established that Eu3+ forms two types of optical centers. Upon the transition of Sr2Gd8(SiO4)6O2:Eu3+ phosphor from bulk state to nanostate during laser excitation, the luminescence intensity of Eu3+ ions increases 10 times. Blue and white amorphous nanophosphors have been obtained for the first time by evaporation of Ca2M8(SiO4)6O2:Eu (M=Y, Gd) and Ca2La8(GeO4)O2:Eu phosphors. Radiation reduction of ions Eu3+→Eu2+ in electron beam has been presumably found.

scholarly journals Новые наноразмерные люминофоры, полученные испарением силикатов и германатов РЗЭ

2019 ◽  
Vol 61 (5) ◽  
pp. 1003
Author(s):  
М.Г. Зуев ◽  
В.Г. Ильвес ◽  
С.Ю. Соковнин ◽  
А.А. Васин ◽  
И.В. Бакланова
Keyword(s):  
Electron Beam ◽  
Raman Scattering ◽  
Amorphous State ◽  
Electron Beam Evaporation ◽  
Ligand Field ◽  
Translational Symmetry ◽  
Pulsed Electron Beam ◽  
Bulk Powder ◽  
Luminescence Characteristics ◽  
The Eu

AbstractNanophosphors in the amorphous state are first obtained via pulsed electron beam evaporation of targets made of polycrystalline phosphors with the compositions Ca_2M_8(SiO_4)_6O_2:Eu (M = Y and Gd) and Ca_2La_8(GeO_4)_6O_2:Eu with the structure of oxyapatite. Reduction of ions Eu^3+ → Eu^2+ in the electron beam is found. Modification of the Raman scattering (RS) spectra of the samples in the case of a decrease in the size of the particles from bulk to a nanosized state is found. The change in the forbidden band width E _ g of the samples in the case of transition from a bulk powder to an NP is considered. The spectral and luminescence characteristics of the samples in the polycrystalline and nanoamorphous states are studied. It is shown that, in the case of transition to nanosamples, the ligand field around Eu^2+ changes. This may be due to the violation of the translational symmetry in the NP. The bond between the 4 f and 5 d electrons weakens. Degeneracy of the ^2 e _ g level appears. Presumably, the reduction of ions Eu^3+ → Eu^2+ in the electron beam due to the breaking of the Si(Ge)–O bond in the process of evaporation of the samples and capture of the released electron by the Eu^3+ ions is found.

scholarly journals Effect of iron doping on the properties of nanopowders and coatings on the basis of Al2O3 produced by pulsed electron beam evaporation

2013 ◽  
Vol 8 (7-8) ◽  
pp. 466-481 ◽  
Author(s):  
S. Yu. Sokovnin ◽  
V. G. Il’ves ◽  
A. I. Surdo ◽  
I. I. Mil’man ◽  
M. I. Vlasov
Keyword(s):  
Electron Beam ◽  
Electron Beam Evaporation ◽  
Iron Doping ◽  
Pulsed Electron Beam

scholarly journals Production of nanopowders of bismuth oxide doped with silver by pulsed electron beam evaporation in vacuum

2021 ◽  
Vol 2064 (1) ◽  
pp. 012106
Author(s):  
V G Ilves ◽  
S Y Sokovnin ◽  
M A Uimin
Keyword(s):  
Electron Beam ◽  
Bismuth Oxide ◽  
Solid Phase ◽  
Electron Beam Evaporation ◽  
Visible Range ◽  
Phase Synthesis ◽  
Pulsed Electron Beam ◽  
Long Term Storage ◽  
Environmentally Friendly Method

Abstract Various bismuth containing compounds are promising in many applications, including for creating photocatalysts based on them using a visible range of light. However, strong polymorphism (9 polymophic phases of Bi2O3), thermal instability and changes in the properties of bismuth oxide during long-term storage significantly complicate work with it. One way to increase stability and improve photocatalytic properties is by doping Bi2O3 with various metals. Ag doped Bi2O3 nanoparticles (NPs) are typically produced using chemical techniques often associated with the presence of toxic chemicals. The present paper used an environmentally friendly method of producing NPs using the method of pulsed electron beam evaporation in vacuum. The evaporation target was obtained by solid phase synthesis in an electric furnace on air using silver nitrate additives (1 and 5 wt.%). Textural, thermal and magnetic properties of the obtained NPs have been studied. Was found that the Ag-Bi2O3 NPs have a specific surface area (SSA) of 23.7 m2/g, which was almost 2 times bigger than the SSA of the pure Bi2O3 (13.2 m2/g) obtained previously. The thermal stability of the Ag-doped Bi2O3 samples was maintained to the temperature 350°C. While further heating on air took place the phase transition β → α

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