Controlling disorder in the ZnGa2O4:Cr3+ persistent phosphor by Mg2+ substitution

Basavaraju, Neelima and Priolkar, Kaustubh R and Bessière, Aurélie and Sharma, Suchinder K and Gourier, Didier and Binet, Laurent and Viana, Bruno and Emura, Shuichi (2016) Controlling disorder in the ZnGa2O4:Cr3+ persistent phosphor by Mg2+ substitution. In: Physical Chemistry Chemical Physics, 19 (2). pp. 1369-1377. ISSN 1463-9076

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Abstract

We have studied in this work the effect of increasing structural disorder on the persistent luminescence of a Cr3+ doped zinc gallate spinel. This disorder was introduced by progressive substitution of Zn2+ by Mg2+ ions, and was studied by photoluminescence, X-ray diffraction, extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES) and electron paramagnetic resonance (EPR) spectroscopy. It was found that increasing the Mg/Zn substitution decreases the number of Cr3+ in undistorted sites and increases the number of Cr3+ with neighbouring antisite defects and with neighbouring Cr3+ ions (referred to as Cr clusters), which in turn decreases the intensity of persistent luminescence. Both XANES and EPR spectra could be simulated by a linear combination of Cr3+ spectra with three types of Cr3+ environments. The increasing disorder was found to be correlated with a decrease of the average Cr-O bond length and a decrease of crystal field strength experienced by Cr3+ ions.

Item Type:	Journal Article
Publication:	Physical Chemistry Chemical Physics
Publisher:	Royal Society of Chemistry
Additional Information:	The Copyright of this article belongs to the Authors.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	03 Jun 2022 05:53
Last Modified:	03 Jun 2022 05:53
URI:	https://eprints.iisc.ac.in/id/eprint/72964

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