About this Journal Submit a Manuscript Table of Contents
Journal of Materials
Volume 2013 (2013), Article ID 613090, 10 pages
http://dx.doi.org/10.1155/2013/613090
Research Article

Giant Improvement on the Afterglow of Sr4Al14O25:Eu2+,Dy3+ Phosphor by Systematic Investigation on Various Parameters

Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502, Japan

Received 28 November 2012; Accepted 22 January 2013

Academic Editor: Necmettin Maraşlı

Copyright © 2013 Hom Nath Luitel et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Highly intense, long persistent Sr4Al14O25:Eu2+,Dy3+ blue-green phosphor with different B3+, Eu2+, Dy3+, and Ag+ contents was prepared by solid-phase reaction at various temperatures in reductive atmosphere of 10% H2 in N2. The effects of synthesis parameters like calcination temperature and time, calcination environment, effect of stoichiometry of the host composition, and additives like addition of boron and rare earth ions (Eu, Dy) were studied in detail. Results revealed that the phosphor containing ~40 mol% H3BO3 showed dense and pure Sr4Al14O25 phase with higher emission intensity, but in the samples containing less than 20 mol% H3BO3 mixed phases consisting of Al2O3, SrAl12O19 and SrAl2O4 were observed, while in higher H3BO3 content, SrAl2B2O7 phases predominated. When the stoichiometry of Al/Sr was 3.7, the best phosphorescence and afterglow were noted. The phosphor containing 4 at.% of Eu and 8 at.% of Dy, and 3 at.% Ag exhibited the maximum initial intensity of 5170 mcd·m−2 and the longest persistency of greater than 30 hours over the value of 5 mcd·m−2, higher than the commercial products and applicable for various display applications involving indoor as well as outdoor uses.