Biswas, Kaushik and Balaji, Sathravada and Ghosh, Debarati and Sontakke, Atul D and Annapurna, K (2014) Near-infrared frequency down-conversion and cross-relaxation in Eu2+/Eu3+-Yb3+ doped transparent oxyfluoride glass and glass-ceramics. Journal of Alloys and Compounds, 608. pp. 266-271. ISSN 0925-8388

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Abstract

In the present work, Eu2+/Eu3+-Yb3+ co-doped SiO2-K2O-BaF2-La2O3-Sb2O3 oxyfluoride glasses were synthesized by conventional melt quenching method to elucidate the cooperative energy transfer (CET) based frequency down conversion from Yb3+ ions under UV excitation. The in situ formation of divalent europium (Eu2+) along with Eu3+ during high temperature synthesis of these glasses under ambient atmosphere has been perceived and was explained through optical basicity model. Frequency down-conversion due to emission of two near infrared photons at around 1 mu m from Yb3+ ions has been realized upon excitation of Eu2+ ions under 286 nm and further enhancement of this frequency down-conversion has been observed upon ceramization of these glasses. The precipitation of BaF2 nano-crystals in glass-ceramics causes reduction of Eu3+ ions to Eu2+ ions resulting in an enhancement in the cooperative energy transfer from Eu2+ to Yb3+. The weak contribution of Eu3+ excitation towards Yb3+ emission has been attributed to the cross-relaxation process via D-5(0) F-7(6) (Eu3+):F-2(5/2) F-2(7/2) (Yb3+) route. The donor (Eu2+/Eu3+)-acceptor (Yb3+) concentration has been optimized at 0.5 mol% Eu2O3 and 1.0 mol% Yb2O3 to achieve maximum down-conversion intensity near 1 mu m. (C) 2014 Elsevier B.V. All rights reserved.

Item Type:	Article
Subjects:	Glass
Divisions:	Glass
Depositing User:	Bidhan Chaudhuri
Date Deposited:	17 Nov 2014 09:52
Last Modified:	11 Jun 2015 06:46
URI:	http://cgcri.csircentral.net/id/eprint/2533

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