title: Rare earth activated yttrium aluminate phosphors with modulated luminescence.
abstract: Yttrium aluminate (Y3 A5 O12 ) 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,Y3-x-a Gdx REa Al5 O12 (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-Y3 Al5 O12 phase as major component along with monoclinic-Y4 Al2 O9 and orthorhombic-YAlO3 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) F5/2 , (2) F7/2 ). 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.
authors.affiliation: 'Babes-Bolyai' University, 'Raluca Ripan' Institute for Research in Chemistry, Fântânele 30, 400294, Cluj-Napoca, Romania.
authors.forename: L E
authors.initials: LE
authors.lastname: Muresan
authors.affiliation: 'Babes-Bolyai' University, 'Raluca Ripan' Institute for Research in Chemistry, Fântânele 30, 400294, Cluj-Napoca, Romania.
authors.forename: E J
authors.initials: EJ
authors.lastname: Popovici
authors.affiliation: 'Babes-Bolyai' University, 'Raluca Ripan' Institute for Research in Chemistry, Fântânele 30, 400294, Cluj-Napoca, Romania.
authors.forename: I
authors.initials: I
authors.lastname: Perhaita
authors.affiliation: National Institute for R&D for Isotopic and Molecular Technologies, Donath 71-103, 400293, Romania.
authors.forename: E
authors.initials: E
authors.lastname: Indrea
authors.affiliation: Institute of Material Science of Barcelona, Campus de la UAB, 08193, Bellaterra, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Oro
authors.affiliation: Institute of Material Science of Barcelona, Campus de la UAB, 08193, Bellaterra, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Casan Pastor
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry*; D008674:Metals, Rare Earth / Q000737:chemistry*; D015019:Yttrium / Q000737:chemistry*
chemical_list: D049408:Luminescent Agents; D008674:Metals, Rare Earth; D015019:Yttrium; D000535:Aluminum
keywords: luminescence; phosphors; rare earth; wet chemical synthesis; yttrium aluminium garnet