Effect of excitation wavelength(blue vs near UV)and dopant concentrations on afterglow and fast decay of persistent phosphor SrAl_(2)O_(4):Eu^(2+),Dy^(3+)

作     者：Bernhard Walfort Nando Gartmann Jafar Afshani Arnulf Rosspeintner Hans Hagemann Bernhard Walfort;Nando Gartmann;Jafar Afshani;Arnulf Rosspeintner;Hans Hagemann

作者机构：LumiNova AGSwitzerlandSpeicherstrasse 60aCH-9053TeufenSwitzerland Dépt.de Chimie PhysiqueUniversitéde Genève30Quai E.AnsermetCH 1211Geneva 4Switzerland 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2022年第40卷第7期

页      面：1022-1028页

核心收录：

学科分类：081702[工学-化学工艺] 0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 0817[工学-化学工程与技术] 0708[理学-地球物理学] 0703[理学-化学] 

基　　金：Project supported by the Swiss National Science Foundation(200020_182494,200021_169033) Innosuisse(25902.1 PFNM-NM,15217.1PFIW-IW) 

主　　题：Persistent phosphor Strontium aluminate Europium Forster energy transfer Rare earths 

摘      要：The persistent phosphor SrAl_(2)O_(4):Eu^(2+),Dy^(3+)is the subject of numerous *** often neglected aspect is that in this phosphor,as well as in Sr_(4)Al_(14)O_(25):Eu^(2+),Dy^(3+),there are two different Sr^(2)+sites which can be occupied by the dopant Eu^(2+)ions,We first introduce a general scheme of possible energy transfers in these persistent phosphor materials including explicitly both europium ions,This scheme is used as a generic starting point to study experimentally specific *** illustrate this application with the study of the effect of excitation wavelength(444 and 382 nm)on the afterglow of differently doped SrAl_(2)O_(4):Eu^(2+),Dy^(3+)samples,as well as on the emission decay *** the same excitation intensity under 444 nm excitation,the resulting afterglow intensity is stronger than under near UV *** 382 nm,Eu^(2+)ions on both Sr^(2)+s ites in SrAl_(2)O_(4)are excited,but at room temperature the blue emission is quenched,leading to a loss of *** observed effects can further be associated with the ratio of Eu^(2+)ions and trap states which are modulated by the concentrations of Eu^(2+)and Dy^(3+)in SrAl_(2)O_(4),as well as by temperature,Increasing the nominal Dy^(3+)content from 0.1 mol%to 0.5 mol%with respect to Sr results in the doubling of the integrated afterglow intensity and confirms thus that Dy^(3+)ions are indeed involved in the trapping process,The concentration of trap states is much lower than the concentration of Eu^(2+)ions,as even with low excitation densities,a plateau of integrated afterglow intensity(corresponding to the total number of accessible traps)is *** postulate that an important fraction of excited Eu^(2+)ions can potentially transfer their energy to trap *** that all traps are filled or in a dynamical filling-depletion process under illumination(with thermal and/or optical depletion processes),for the remaining Eu^(2+)anormalsteady-state emission is observed