Singh, Vijay and Chakradhar, R P S and Rao, J L and Kim, Dong-Kuk (2008) Luminescence and EPR studies of Mn-activated SrAl12O19 phosphor prepared by facile combustion approach. Physica B-Condensed Matter, 403 (1). pp. 120-125. ISSN 0921-4526

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Manganese-activated strontium hexa-aluminate (SrAl12O19) phosphor has been prepared at low temperature (500 degrees C) and in a very short time (<5 min) by urea combustion route. Powder X-ray diffraction pattern showed the presence of hexagonal SrAl12O19 phase. Scanning electron microscopy (SEM) indicated the presence of several particles with sizes of 200 nm. The luminescence of Mn2+ activated SrAl12O19 exhibits a strong green emission peak around 515 nm from the synthesized phosphor particles under excitation (451 nm). The luminescence is assigned to a transition from the upper T-4(1) -> (6)A(1) ground state of Mn2+ ions. EPR investigations also indicated the presence of Mn2+ ions in the prepared material. From the observed EPR spectrum, the spin-Hamiltonian parameters have been evaluated. The magnitude of the hyperfine splitting (A) constant indicates that there exists a moderately covalent bonding between Mn2+ ions and the surrounding ligands. The variation of zero-field splitting parameter (D) with temperature is measured and discussed. The mechanism involved in the generation of a green emission has been explained in detail. (C) 2007 Elsevier B.V. All rights reserved.

Item Type: Article
Uncontrolled Keywords: combustion; photoluminescence; EPR; Mn2+ ions; phosphors
Subjects: Processing Science
Depositing User: Bula Ghosh
Date Deposited: 20 Jan 2012 10:09
Last Modified: 05 Apr 2016 10:16

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