Sol-Gel Preparation and Luminescence Properties of BaMgAl10O17 : Eu 2+ Phosphors

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JOURNAL OF RARE EARTHS 24(2006)706—7 1 1 

Sol-Gel Preparation and Luminescence 

BaMgAI1o O17:Eu2+Phosphors 

Chung—Hsin Lu 。Chung.Tao Chen ,Baibaswata Bhattacharjee 

(,.Department of Chemical 

Physics,Ramananda College, JOURNAL OF E 

WWW.elsevier.c0m/10cate/jre 

Engineering,National Taiwan Unwe ̄ity,Taipei,China;2.Department of 

Bishnupur,Bankura,West Bengal,India,722 122) 

Received 20 June 20o6:revised 13 0letober 2006 

Abstract:卟e synthesis of BaMgA110O17:Eu (BAM)phosphors using the sol—gel method and their luminescence proper— 

ties were reported.The blue—light emitting BAM was synthesized using citric acid and ethylene glycol as chel ̄ing materi— als.Emission of blue.1ight was obtained from these phosphors. e luminescent intensity increases as the temperature of heat treatment is increased.This study investigated the effects of the molar ratio of ethylene glycol to citric acid( val— 

ue).with respect to the phase formation and luminescence properties of BAM.卟e variation of the value resulted in the 

change of the sol—gel reaction mechanism and the microstructures of the resultant powders.An increase in value leads to an increase in the rate of BAM phase formation.The photoluminescent intensity of the prepared phosphors increases with heating temperatures because of enhanced crystallization. 

Key words:phosphors;sol—gel;synthesis;luminescent properties;Iare earths 

CLC number:0482.31 Document code:A Article ID:1002—0721(2006)06—0706—06 

Aluminate phosphors activated with rare earth are 

especially stable and efficient in general lighting of lamps….With the recent advancement.aluminate 

phosphors are intensely fcIcased on Eu“一doped BAM 

phosphors for application in plasma display panels (PDPs)[ ].Barium magnesium aluminate BaMgAl10 

O17(BAM)is classified into l3一alumina structure with a 

space group P63/mmc .The diferent sites occupied 

by the europium ions in the BAM structure have been studied by several researchers_6一lOJ.Boolchand et a1. reported that the Eu”sites occupy the Beevers—Ross. 

anti—Beevers—Ross.and the mid—oxygen sites in BAM: Eu“L6J.The host lattice plays an important role for 

varying the luminescence properties of the phos— phors_llI 12].Howe et a1.[ ]investigated the host—lat— 

tice emission and energy transfer in undoped and Eu— 

doped BAM.They reported that the BAM host lattice showed an emission under vacuum ultraviolet(vuv) 

excitation and this result was assigned to Ba—O groups. 

BAM phosphors are usually prepared by the sol— 

id-state reaction method.In this kind of process, high—temperature heating is required.It is reported 

that an increase in heating temperature leads to an in— 

creased particle size and the surface morphology is also varied[ 引.The Pechini sol—gel method utilizes citric 

acid and ethylene glycol derived polyester resin,com— 

prising branched polymer for the synthesis.This meth— 

od has the ability to synthesize muhicomponent oxides 

with a good homogeneity at a decreased temperature of heat treaⅡnent【 4,15]. Several I.eseaI℃hers have used the method to prepare BAM:Eu phosphors[16.17]. The effects of ethylene glycol and citric acid ratio on 

the phase formation and luminescent properties of BAM:Eu“phosphors have not been studied in de一 

*Corres ̄nding author(E—mall:chlu@ntu.edu.tw) Biography:Chung-Hsin Lu(1961一),Male,Professor;Majoring in electronic and electro.optical ceramics.nanoparticles and thin-film technology 

Copyright@2OO6,by Editorial Committee of Journal ofthe Chinese Rare Earths Society.Published by Elsevier B.V.ml rights rescued

 维普资讯 http://www.cqvip.com Chung-Hsin Lu et a1.Preparation and Properties ofBaMgAIO:Eu Phosphors 

tail.Accordingly,the purpose of this study is to in— vestigate the effects of the molar ratio of ethylene gly— 

col to citric acid( value)on the synthesized process 

of BAM:Eu“phosphors.The influence of heating 

conditions on the microstructures and luminescent 

properties of the obtained phosphors was also studied 

here. 

Europium—ion—doped barium magnesium alumi— 

nate(BAM:Eu )powders were prepared by the sol— 

gel process using citric acid(Nacalai,guaranteed re— 

agent grade)as a chelating agent and ethylene glycol (Nacalai,guaranteed reagent grade)as a polymerizing 

agent.As shown in Fig.1,barium nitrate(Janssen 

Chimica;No.2O.325.42,99%)。aluminum nitrate 

nonahydrate(Sigma—Aldrich;No.237973,98%, 

ACS reagent grade),magnesium nitrate hexahydrate 

(Nacalai teaque;guaranteed reagent grade),and eu— ropium oxide(Aldrich;No.289221,99.9%)were 

used as starting materials.Europium oxide was dis— 

solved in nitric acid solution(4O%nitric acid).The