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Journal of Nanomaterials
Volume 2015, Article ID 298692, 7 pages
http://dx.doi.org/10.1155/2015/298692
Research Article

Size-Dependent Optical Properties of Nanoscale and Bulk Long Persistent Phosphor SrAl2O4:Eu2+, Dy3+

1Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, China
2Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China

Received 27 December 2014; Revised 13 March 2015; Accepted 14 March 2015

Academic Editor: Yong Zhu

Copyright © 2015 Xiaoxia Duan 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

Nanoscale long persistent phosphor SrAl2O4:Eu2+, Dy3+ was prepared by autocombustion of citrate gel. The energy level shift of activator Eu2+ and coactivator Dy3+ was analyzed according to the emission and the excitation spectra. The band gap change of SrAl2O4 and the resulting trap depth change with particle size were discussed on the basis of analyzing the visible spectra, the vacuum ultraviolet (VUV) excitation spectra, and the thermoluminescence (TL) spectra. The fluorescence quenching and the shallow traps originating from surface adsorption or surface defects explain the weak initial persistent phosphorescence and the fast phosphorescence decay in nanometer SrAl2O4:Eu2+, Dy3+. It is confirmed that energy level, band gap, trap depth, defect, and surface adsorption are deeply related with each other in this nanoscale long persistent phosphor.