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Rare earth activated yttrium aluminate phosphors with modulated luminescence
Author(s) -
Muresan L. E.,
Popovici E. J.,
Perhaita I.,
Indrea E.,
Oro J.,
Casan Pastor N.
Publication year - 2016
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.3051
Subject(s) - phosphor , yttrium , ionic radius , materials science , orthorhombic crystal system , luminescence , analytical chemistry (journal) , monoclinic crystal system , activator (genetics) , ion , aluminate , lanthanide , tetragonal crystal system , doping , crystal structure , chemistry , crystallography , optoelectronics , metallurgy , biochemistry , organic chemistry , chromatography , cement , gene , oxide
Yttrium aluminate (Y 3 A 5 O 12 ) was doped with different rare earth ions (i.e. Gd 3+ , Ce 3+ , Eu 3+ and/or Tb 3+ ) in order to obtain phosphors (YAG:RE) with general formula,Y 3‐x‐a Gd x RE a Al 5 O 12 (x = 0; 1.485; 2.97 and a = 0.03). The synthesis of the phosphor samples was done using the simultaneous addition of reagents technique. This study reveals new aspects regarding the influence of different activator ions on the morpho‐structural and luminescent characteristics of garnet type phosphor. All YAG:RE phosphors are well crystallized powders containing a cubic‐Y 3 Al 5 O 12 phase as major component along with monoclinic‐Y 4 Al 2 O 9 and orthorhombic‐YAlO 3 phases as the impurity. The crystallites dimensions of YAG:RE phosphors vary between 38 nm and 88 nm, while the unit cell slowly increase as the ionic radius of the activator increases. Under UV excitation, YAG:Ce exhibits yellow emission due to electron transition in Ce 3+ from the 5d level to the ground state levels ( 2 F 5/2 , 2 F 7/2 ). The emission intensity of Ce 3+ is enhanced in the presence of the Tb 3+ ions and is decreased in the presence of Eu 3+ ions due to some radiative or non‐radiative processes that take place between activator ions. By varying the rare earth ions, the emission colour can be modulated from green to white and red. Copyright © 2015 John Wiley & Sons, Ltd.