Boulevard Frantz Fanon

Algiers, Algeria

Boulevard Frantz Fanon

Algiers, Algeria
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Kahouadji B.,University of Abderrahmane Mira de Béjaïa | Guerbous L.,Boulevard Frantz Fanon | Boukerika A.,Boulevard Frantz Fanon | Dolic S.D.,Vinča Institute of Nuclear Sciences | And 2 more authors.
Optical Materials | Year: 2017

Pr3+ -doped YPO4 nanophosphors prepared by simple sol gel method with different pH values (2, 4, 7 and 11) were obtained. The nanopowders samples were characterized by X-ray diffraction (XRD), room temperature steady and time resolved photoluminescence spectroscopy. The thorough study of pH influence on particle's structure and luminescence of YPO4: 1 at. Pr3+ is presented. It was found that the grain size of samples increases with increases in pH value and obtained particles crystallize in a tetragonal phase with xenotime structure. Under 4f5d excitation (230 nm), all emission spectra show the inter-configurational 4f2→4f5d and under 3P2 excitation (449 nm), only the intra-configurational 1D2→3H4 red emission transition between 580 nm and 620 nm are observed. The highest luminescent intensity was obtained for samples prepared at pH = 4. Furthermore, it was found that the pH of solution has no effect of 1D2 lifetime. © 2017 Elsevier B.V.


Lamiri L.,University of Abderrahmane Mira de Béjaïa | Guerbous L.,Boulevard Frantz Fanon | Samah M.,University of Abderrahmane Mira de Béjaïa | Boukerika A.,Boulevard Frantz Fanon | Ouhenia S.,University of Abderrahmane Mira de Béjaïa
Luminescence | Year: 2015

Europium trivalent (Eu3+)-doped Y2O3 nanopowders of different concentrations (0.5, 2.5, 5 or 7 at.%) were synthesized by the sol-gel method, at different pH values (pH 2, 5 or 8) and annealing temperatures (600°C, 800°C or 1000°C). The nanopowders samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and steady state photoluminescence spectroscopy. The effect of pH of solution and annealing temperatures on structural, morphological and photoluminescence properties of Eu3+-doped Y2O3 were studied and are discussed. It was found that the average crystallite size of the nanopowders increased with increasing pH and annealing temperature values. The Y2O3:Eu3+ material presented different morphology and its evolution depended on the pH value and the annealing temperature. Activation energies at different pH values were determined and are discussed. Under ultraviolet (UV) light excitation, Y2O3:Eu3+ showed narrow emission peaks corresponding to the 5D0- 7FJ (J = 0, 1, 2 and 3) transitions of the Eu3+ ion, with the most intense red emission at 611 assigned to forced electric dipole 5D0→7F2. The emission intensity became more intense with increasing annealing temperature and pH values, related to the improvement of crystalline quality. For the 1000°C annealing temperature, the emission intensity presented a maximum at pH 5 related to the uniform cubic-shaped particles. It was found that for lower annealing temperatures (small crystallite size) the CTB (charge transfer band) position presented a red shift. © 2015 John Wiley & Sons, Ltd.


Lamiri L.,Boulevard Frantz Fanon | Lamiri L.,University of Abderrahmane Mira de Béjaïa | Guerbous L.,Boulevard Frantz Fanon | Samah M.,University of Abderrahmane Mira de Béjaïa | And 2 more authors.
Luminescence | Year: 2015

Europium trivalent (Eu3+)-doped Y2O3 nanopowders of different concentrations (0.5, 2.5, 5 or 7 at.%) were synthesized by the sol-gel method, at different pH values (pH 2, 5 or 8) and annealing temperatures (600 C, 800 C or 1000 C). The nanopowders samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and steady state photoluminescence spectroscopy. The effect of pH of solution and annealing temperatures on structural, morphological and photoluminescence properties of Eu3+-doped Y2O3 were studied and are discussed. It was found that the average crystallite size of the nanopowders increased with increasing pH and annealing temperature values. The Y2O3:Eu3+ material presented different morphology and its evolution depended on the pH value and the annealing temperature. Activation energies at different pH values were determined and are discussed. Under ultraviolet (UV) light excitation, Y2O3:Eu3+ showed narrow emission peaks corresponding to the 5D0- 7FJ (J = 0, 1, 2 and 3) transitions of the Eu3+ ion, with the most intense red emission at 611 assigned to forced electric dipole 5D0→7F2. The emission intensity became more intense with increasing annealing temperature and pH values, related to the improvement of crystalline quality. For the 1000 C annealing temperature, the emission intensity presented a maximum at pH 5 related to the uniform cubic-shaped particles. It was found that for lower annealing temperatures (small crystallite size) the CTB (charge transfer band) position presented a red shift. Copyright © 2015 John Wiley & Sons, Ltd.


PubMed | University of Abderrahmane Mira de Béjaïa and Boulevard Frantz Fanon
Type: Journal Article | Journal: Luminescence : the journal of biological and chemical luminescence | Year: 2016

Europium trivalent (Eu(3+))-doped Y2O3 nanopowders of different concentrations (0.5, 2.5, 5 or 7 at.%) were synthesized by the sol-gel method, at different pH values (pH 2, 5 or 8) and annealing temperatures (600 C, 800 C or 1000 C). The nanopowders samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and steady state photoluminescence spectroscopy. The effect of pH of solution and annealing temperatures on structural, morphological and photoluminescence properties of Eu(3+)-doped Y2O3 were studied and are discussed. It was found that the average crystallite size of the nanopowders increased with increasing pH and annealing temperature values. The Y2O3:Eu(3+) material presented different morphology and its evolution depended on the pH value and the annealing temperature. Activation energies at different pH values were determined and are discussed. Under ultraviolet (UV) light excitation, Y2O3:Eu(3+) showed narrow emission peaks corresponding to the (5)D0- (7) FJ (J = 0, 1, 2 and 3) transitions of the Eu(3+) ion, with the most intense red emission at 611 assigned to forced electric dipole (5)D0 (7)F2. The emission intensity became more intense with increasing annealing temperature and pH values, related to the improvement of crystalline quality. For the 1000 C annealing temperature, the emission intensity presented a maximum at pH 5 related to the uniform cubic-shaped particles. It was found that for lower annealing temperatures (small crystallite size) the CTB (charge transfer band) position presented a red shift.

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