第 43 卷第 7 期
2015 年 7 月
硅 酸 盐 学 报
Vol. 43,No. 7
July,2015
JOURNAL OF THE CHINESE CERAMIC SOCIETY
http://www.gxyb.cbpt.cnki.net DOI:10.14062/j.issn.0454-5648.2015.07.16
白光 LED 用红色发光材料 CaLa
2
(MoO
4
)
4
:Eu
3+
的微波辅助溶胶–凝胶
法合成及发光特性
翟永清,李金航,李
璇,宋珊珊,曹丽丽
(河北大学化学与环境科学学院,河北 保定 071002)
摘 要:以柠檬酸为络合剂,采用微波辅助溶胶–凝胶法制备了 CaLa
2
(MoO
4
)
4
:Eu
3+
红色荧光粉。研究了前驱体的热分解历程,
分析表征了样品的结构、形貌和发光性能。探讨了焙烧温度、Eu
3+
掺杂量、柠檬酸与乙二醇摩尔比和硼酸用量等对样品发光
性能的影响。结果表明:前驱体经 700~900
℃焙烧均能得到目标产物 CaLa
2–x
(MoO
4
)
4
:xEu
3+
,样品具有白钨矿结构,属于四
方晶系。样品的激发光谱在 250~350 nm 处有一宽吸收带,对应于 Mo–O,Eu–O 电荷迁移带;在 395 和 464
nm 处存在很强
的吸收峰,归属于 Eu
3+
的 4f–4f 跃迁。发射光谱主峰位于 616
nm 处,归属于 Eu
3+
的
5
D
0
→
7
F
2
电偶极跃迁发射。前驱体经 800
℃
焙烧所得样品发光强度最大,且发光强度随着 Eu
3+
掺杂量的增加而增大,在 x=0.2~1.0 范围内未出现猝灭现象。体系中加入
适量乙二醇,可以起到细化晶粒、提高粉体分散性的作用,但浓度过高则会降低样品的发光强度;助熔剂硼酸的用量对样品
发光强度影响较大,当用量为 3%时,样品的发光性能较好。
关键词:钼酸镧钙;铕离子;微波辅助溶胶–凝胶法;红色发光粉
中图分类号:O482.31 文献标志码:A 文章编号:0454–5648(2015)07–0952–07
网络出版时间:2015–05–27 18:47:31 网络出版地址:http://www.cnki.net/kcms/detail/11.2310.TQ.20150527.1847.008.html
Synthesis and Luminescent Properties of CaLa
2
(MoO
4
)
4
:Eu
3+
Red-emitting Phosphors for
White LED by Microwave-assisted Sol–gel Method
ZHAI Yongqing, LI Jinhang, LI Xuan, SONG Shanshan, CAO Lili
(College of chemistry and environmental science, Hebei University, Baoding 071002, Hebei, China)
Abstract: The red-emitting CaLa
2
(MoO
4
)
4
:Eu
3+
powders
were prepared by a microwave-assisted sol-gel method, with citric acid as a
chelating agent. The heat decomposion mechanism of the precursor, phase structure, morphology and luminescent properties of the
samples were characterized. The influences of calcining temperature, Eu
3+
content, mole ratio of citric to ethylene glycol (EG) and the
dosage of H
3
BO
3
on the luminescent properties of the samples were investigated. The results indicate that the target products of
CaLa
2–x
(MoO
4
)
4
:xEu
3+
are synthesized by calcining precursor in a temperature range from 700 ℃ to 900 ℃. The products are
readily indexed to a pure tetragonal phase with scheelite structure. The excitation spectra consist of a broad band at 250–350
nm and
the intense lines at 395 nm and 464 nm. The former is attributed to the Mo–O and Eu–O charge transfer transition, and the latter is
due to 4f–4f transitions of Eu
3+
ions. In the emission spectra, the main peak centered at 616 nm corresponds to the
5
D
0
→
7
F
2
electronic
dipole transition. The luminescence intensity of the sample obtained at 800 ℃ is the maximum, and it increases gradually with the
increase of Eu
3+
concentration. Little concentration quenching occurs when the value of x is in the range of 0.2–1.0. In addition, the
addition of an appropriate amount of ethylene glycol in the solvent may contribute to the grain refinement and the powder dispersion.
A high concentration of ethylene glycol will reduce the luminescence intensity of the sample. The dosage of flux H
3
BO
3
has a great
effect on the luminescence intensity of the sample. When the dosage of H
3
BO
3
is 3%, the luminescence intensity of the sample shows
better luminescent properties.
Key words: lanthanum calcium molybdate; europium ion; sol-gel method assisted by microwave; red-emitting phosphors
收稿日期:2014–11–20。 修订日期:2015–01–20。
基金项目:国家自然科学基金(21301046)资助项目。
第一作者:翟永清(1970—),女,博士,教授。
Received date: 2014–11–20. Revised date: 2015–01–20.
First author: ZHAI Yongqing (1970–), female, Ph.D., Professor.
E-mail: zhaiyongqinghbu@163.com