Singh, Shiv Prakash and Chakradhar, R P S and Rao, J L and Karmakar, Basudeb (2010) EPR, optical absorption and photoluminescence properties of MnO(2) doped 23B(2)O(3)-5ZnO-72Bi(2)O(3) glasses. Physica B-Condensed Matter, 405 (9). pp. 2157-2161. ISSN 0921-4526

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Electron paramagnetic resonance (EPR), transmission electron microscopy (TEM), optical absorption and photoluminescence (PL) spectroscopic measurements are performed on Mn(2+) doped high bismuth containing zinc-bismuth-borate glasses. TEM images reveal homogeneously dispersed Bi(circle) nanoparticles (NPs) of spherical shape with size about 5 nm. EPR spectra exhibit predominant signals at g approximate to 2.0 and 4.3 with a sextet hyperfine structure. The resonance signal at g approximate to 2.0 is due to Mn(2+) ions in an environment close to octahedral symmetry, where as the resonance at g approximate to 4.3 is attributed to the rhombic surrounding of the Mn(2+) ions. The hyperfine splitting constant (A) indicates that Mn(2+) ions in these glasses are moderately covalent in nature. The zero-field splitting parameter D has been calculated from the allowed hyperfine lines. The optical absorption spectrum exhibits a single broad band centered at 518 nm (19,305 cm(-1)) is assigned to the (6)A(1g)(S) —> (4)T(1g)(G) transition of Mn(2+) ions. The visible and near infrared (NIR) luminescence bands at 548, 652 and 804 nm have been observed when excited at 400 and 530 nm, respectively. These luminescence centers are supposed to be caused by the lower valence state of bismuth, such as Bi(2+) and Bi(+) ions, generated during melting process. (C) 2010 Elsevier B.V. All rights reserved.

Item Type: Article
Uncontrolled Keywords: Glasses; Mn(2+) ions; EPR; TEM; Optical absorption; Photoluminescence
Subjects: Glass
Depositing User: Bidhan Chaudhuri
Date Deposited: 16 Feb 2012 07:50
Last Modified: 27 Mar 2012 08:23

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