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Structural, morphological and steady state photoluminescence spectroscopy studies of red Eu 3+ ‐doped Y 2 O 3 nanophosphors prepared by the sol‐gel method
Author(s) -
Lamiri Lyes,
Guerbous Lakhdar,
Samah Madani,
Boukerika Allaoua,
Ouhenia Salim
Publication year - 2015
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.2903
Subject(s) - photoluminescence , analytical chemistry (journal) , annealing (glass) , europium , crystallite , spectroscopy , materials science , doping , fourier transform infrared spectroscopy , scanning electron microscope , luminescence , sol gel , electric dipole transition , magnetic dipole transition , chemistry , dipole , nanotechnology , optics , physics , magnetic dipole , organic chemistry , optoelectronics , chromatography , quantum mechanics , metallurgy , composite material
Abstract Europium trivalent (Eu 3+ )‐doped Y 2 O 3 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 Y 2 O 3 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 Y 2 O 3 :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, Y 2 O 3 :Eu 3+ showed narrow emission peaks corresponding to the 5 D 0– 7 F J (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 D 0 → 7 F 2 . 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.