Effect of Composition and Impurities on the Phosphorescence of Green-Emitting Alkaline Earth Aluminate Phosphor

Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness i...

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Bibliographic Details
Published in:PloS one 2016, Vol.11 (1), p.e0145434-e0145434
Main Authors: Kim, Doory, Kim, Han-Eol, Kim, Chang-Hong
Format: Article
Language:English
Subjects:
Alkali metals
Alkaline earth metals
Aluminum Oxide - chemistry
Brightness
Chemistry
Composition effects
Copper
Crystal structure
Crystallization
Crystals
Doping
Dysprosium - chemistry
Earth
Europium
Europium - chemistry
Impurities
Kinetics
Light
Lithium - chemistry
Luminescence
Luminescent Agents - chemistry
Luminescent Measurements - methods
Magnesium
Magnesium - chemistry
Metals
Phosphorescence
Phosphors
Silicon - chemistry
Spectrometry, Fluorescence
Strontium - chemistry
Time Factors
Zinc sulfide
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Summary:Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness in SrAl2O4:Eu2+, Dy3+ phosphors remains a challenging task. Here, we have improved the afterglow characteristics in terms of persistence time and brightness by a systematic investigation of the composition of Eu-doped alkaline earth aluminate SrAl2O4:Eu2+, Dy3+ crystals. We found that a Dy3+/Eu2+ ratio of ~2.4 and ~0.935 mol Eu2+ (per mol of SrAl2O4) gave the brightest and longest emissions (11% and 9% increase for each). Doping with Si4+ also resulted in a slight increase in brightness up to ~15%. Doping with alkali metal or alkaline earth metal significantly enhanced the phosphorescence intensity. In particular, doping with 0.005 mol Li+ (per mol of SrAl2O4) alone boosted the phosphorescence intensity to 239% of the initial value, as compared to that observed for the non-doped crystal, while doping with 0.01 mol Mg2+ and 0.005 mol Li+ (per 1 mol SrAl2O4) boosted the phosphorescence intensity up to 313% of the initial value. The results of this investigation are expected to act as a guideline for the synthesis of bright and long persistent phosphors, and facilitate the development of persistent phosphors with afterglow characteristics superior to those of conventional phosphors.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0145434