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Materials, Methods & Technologies, Volume 13, 2019

DYSPROSIUM DOPED CALCIUM GERMANATE (CA2GеO4) AS A CANDIDATE FOR LED APPLICATION
Iovka I. Koseva, Peter Tz. Tzvetkov, Petar I. Ivanov, Maria N. Gancheva, Velin S. Nikolov
Pages: 18-24
Published: 18 Sep 2019
Views: 263
Downloads: 72
Abstract: Powder samples of Ca2GeO4 doped with 0.2, 0.5, 1, 2 and 3 at% Dy3+ were prepared using conventional solid state synthesis technique. XRD analyses show obtaining of the pure phase at all dopant concentrations. Emission and excitation spectra contain the characteristic peaks of Dy3+ ion. The Dy3+ excitation spectrum in the range from 300 to 500 nm show characteristic transitions of Dy3+, attributed to the f–f transitions. The strongest peak is located at 348 nm corresponding to the 6H15/2 →6P7/2 transition. In the luminescent spectra the two emission peaks of Dy3+ appears at 483 nm (4F5/2 →6H15/2 transition) corresponding to blue color and at 575 nm (4F5/2→6H13/2 transition) corresponding to yellow one. CIE coordinates of the samples show different emission colors in the yellow region depending on the active ion concentration. The obtained results confirm that as prepared dysprosium doped materials could be used as yellow phosphors.
Keywords: germanate phosphor, materials for led, rare-earth ions, x-ray diffraction, photoluminescence
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