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Autori: Laura E. Muresan, Elisabeth-Jeanne Popovici, I. Perhaita, Emil Indrea, Teofil Danut Silipas
Editorial: ELSEVIER, Materials Science and Engineering B, 178(4), p.248 - 253, 2013.
Europium activated yttrium aluminate (YAG:Eu) phosphors were synthesized using urea by wet chemical synthesis route. The luminescent behavior and the microstructural changes are monitored, depending on the amount of europium. The luminescent spectra of YAG:Eu phosphors possess four major emission bands in the range of 570–700 nm with maxima situated at 592 nm 598 nm, 611 nm and 631 nm. The intensity ratio between the 611 nm band as red component (5D0→7F2) and 592 nm band as orange component (5D0→7F1) is discussed, in order to obtain information about the chemical surroundings of the luminescent centers and their symmetry. X-ray diffraction showed that the main crystalline phase of the phosphors is yttrium aluminum garnet Y3Al5O12 with cubic structure. Monoclinic Y4Al2O9 phase was also found as impurity. The effect of the europium content on the microstructural parameters is revealed. The luminescent characteristics depend strongly on the structural purity, activator concentration and incorporation of europium ions in the host lattice. Additional investigations as FT-IR, BET, ICP-OES were performed for a better understanding of the luminescent and structural characteristics of YAG:Eu phosphor.
Cuvinte cheie: Europium activated yttrium aluminate (YAG:Eu) phosphors , luminescent centers , X-ray diffraction