Photoluminescence of $Eu^{2+}$-doped mullite $(xAl_2O_3{\cdot}ySiO_2;x/y =\frac{3}{2}\hspace{2mm}and\hspace{2mm} \frac{2}{1})$ prepared by a hydrothermal method

Kutty, TRN and Nayak, M (2000) Photoluminescence of $Eu^{2+}$-doped mullite $(xAl_2O_3{\cdot}ySiO_2;x/y =\frac{3}{2}\hspace{2mm}and\hspace{2mm} \frac{2}{1})$ prepared by a hydrothermal method. In: Materials Chemistry and Physics, 65 (2). pp. 158-165.

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Abstract

Mullite with different $Al_2O_3/SiO_2$ ratios $(\frac{3}{2}\hspace{2mm}and\hspace{2mm}\frac{2}{1})$ is prepared by the decomposition of the precursor prepared by the hydrothermal method at above $1300^oC$. The phase relations and thermal events during the decomposition are studied by powder X-ray diffraction and thermal analyses. Presence of defect centres is revealed by electron paramagnetic resonance (EPR) spectroscopy and are nonemissive. $Eu^{2+}$-doped mullite shows blue luminescence and the luminescence characteristics showcomposition dependence. The emission maximum of $Eu^{2+}$-doped $\frac{3}{2}$-mullite is around 460 nm and that of $Eu^{2+}$-doped $\frac{2}{1}$-mullite is around 420 nm. Shift in the emission maxima with change in the $Al_2O_3/SiO_2$ ratio is explained based on the relative change in covalency. Based on photoluminescence studies, site preference of $Eu^{2+}$-doped mullite is assigned to structural cavity rather than to 6- or 4-coordinated regular lattice sites.

Item Type:	Journal Article
Publication:	Materials Chemistry and Physics
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Photoluminescence;Mullite;Aluminosilicate;Europium;Hydrothermal synthesis
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	18 Aug 2006
Last Modified:	19 Sep 2010 04:30
URI:	http://eprints.iisc.ac.in/id/eprint/8075

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