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1 Polish Journal of Chemistry

1 2007

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Effect of Polymer Cations on Photoluminescence Properties of Blue Emitting Alkaline-Earth Metals and Silicon Based Phosphors

Rahman M., Kida T., Nagano M., Khan M.

Polish Journal of Chemistry

2007

Vol. 81, nr 2

249-255

Efficient blue emitting phosphors were prepared by depositing mixed hydroxides of Ca, Sr, Ba, Mg, Eu over spherical SiO2 particles from tetra-ethyl-orthosilicate (TEOS) pre-coated with polycations (polyethyleneimine: PEI) followed by calcination at 1200C in a reducing atmosphere. The prepared phosphor showed intense blue emission, which can be ascribed to 4f 7-4f 65d interconfiguration transitions of Eu2+ ions. In contrast, the luminescence intensity of the phosphor was much decreased when prepared without polycations. It was suggested that negatively charged hydroxides are deposited on positively charged SiO2 surfaces pre-coated with polycations through electrostatic self-assembly interaction. The common formula of the prepared phosphors is AMgSi2O6:Eu2+ (A= Ca, Sr, Ba or fraction of Ca and Sr), where alkaline-earth/Si = 1, the each entire sample was prepared by treating with polycations and without polycations.