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Luminescence of $Eu^{2+}$ in strontium aluminates prepared by the hydrothermal method

Kutty, TRN and Jagannathan, R and Rao, RP (1990) Luminescence of $Eu^{2+}$ in strontium aluminates prepared by the hydrothermal method. In: Materials Research Bulletin, 25 (11). pp. 1355-1362.

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Preparation of Sr-aluminates in fine powder form, with Al/Sr ratio varying from 2 to 12 has been attempted by the hydrothermal method, starting from $Al_2O_3.xH_2O$ gel containing europium and $Sr(OH)_2$ at 240 – $250^0C$. The products are annealed at 850 – 1150°C in $N_2 + H_2$ atmosphere to yield, efficient blue to green luminescent phosphors. The predominant phase isolated belongs to the family of ‘stuffed’ tridymite-nepheline structures, having the general formula, $Sr_n Al_2O_{3+n}$ where n $\leq$ 1. With decreasing n-value, the relative intensity of the 405 nm emission band increases in preference to that of the 510 nm emission. The excitation spectra as well as the EPR results indicate the presence of $Eu^{2+}$ in the vacancy-associated nonequivalent sites. In presence of $H_3BO_3$ in the hydrothermal medium, aluminoborates such as $SrAl_5BO_{10}, Sr_2Al_2B_2O_8$ and $Sr_3Al_6B_8O_{24}$ are produced, whose only emission maximum around 400 nm remains as a band even at $LN_2$ temperature.

Item Type: Journal Article
Publication: Materials Research Bulletin
Publisher: Pergamon Press plc.
Additional Information: Copyright of this article belongs to Pergamon Press plc.
Keywords: Strontium;aluminates;europium;phosphors
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 11 Dec 2007
Last Modified: 19 Sep 2010 04:41
URI: http://eprints.iisc.ac.in/id/eprint/12468

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