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EPR and photoluminescence studies of ZnO:Mn nanophosphors prepared by solution combustion route

Reddy, Jagannatha A and Kokila, MK and Nagabhushana, H and Rao, JL and Nagabhushana, BM and Shivakumara, C and Chakradhar, RPS (2011) EPR and photoluminescence studies of ZnO:Mn nanophosphors prepared by solution combustion route. In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 79 (3). pp. 476-480.

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Official URL: http://dx.doi.org/10.1016/j.saa.2011.03.014


Nanocrystalline ZnO:Mn (0.1 mol%) phosphors have been successfully prepared by self propagating, gas producing solution combustion method. The powder X-ray diffraction of as-formed ZnO:Mn sample shows, hexagonal wurtzite phase with particle size of similar to 40 nm. For Mn doped ZnO, the lattice parameters and volume of unit cell (a=3.23065 angstrom, c=5.27563 angstrom and V=47.684 (angstrom)(3)) are found to be greater than that of undoped ZnO (a=3.19993 angstrom, c=5.22546 angstrom and V=46.336 (angstrom)(3)). The SEM micrographs reveal that besides the spherical crystals, the powders also contained several voids and pores. The TEM photograph also shows the particles are approximately spherical in nature. The FTIR spectrum shows two peaks at similar to 3428 and 1598 cm(-1) which are attributed to O-H stretching and H-O-H bending vibration. The PL spectra of ZnO:Mn indicate a strong green emission peak at 526 nm and a weak red emission at 636 nm corresponding to T-4(1) -> (6)A(1) transition of Mn2+ ions. The EPR spectrum exhibits fine structure transition which will be split into six hyperfine components due to Mn-55 hyperfine coupling giving rise to all 30 allowed transitions. From EPR spectra the spin-Hamiltonian parameters have been evaluated and discussed. The magnitude of the hyperfine splitting (A) constant indicates that there exists a moderately covalent bonding between the Mn2+ ions and the surrounding ligands. The number of spins participating in resonance (N), its paramagnetic susceptibility (chi) have been evaluated. (C) 2011 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Publication: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Publisher: Elsevier Science
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: ZnO:Mn;Diluted magnetic semiconductor (DMS);Electron paramagnetic resonance (EPR);Luminescence
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 05 Jul 2011 10:06
Last Modified: 05 Jul 2011 10:06
URI: http://eprints.iisc.ac.in/id/eprint/38872

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