摘要
以金属硝酸盐为原料,丙烯酰胺为聚合单体以及N,N-亚甲基双丙烯桥酰胺为胶联剂,采用高分子网络凝胶法在低温下合成精细粒度Y_3Al_5O_(12):Tb^(3+)(YAG:Tb^(3+))荧光粉。分别用热重-差热分析(TG-DTA)、X射线衍射(XRD)、扫描电子显微镜(SEM),以及激发和发射光谱测量对样品进行了表征,考察了烧结温度对样品结晶程度、颗粒大小的影响,以及样品发光性能与烧结温度和Tb^(3+)浓度的关系。结果表明:YAG晶相形成温度为850℃;粉体颗粒大小均匀,随着烧结温度的升高,颗粒粒径增大,结晶程度提高;观察到Tb^(3+)中4f-5d的吸收带以及~5D_4-~7F_j(j=6,5,4,3)的特征发射带,最强吸收与最强发射分别发生在272,541.8 nm,与量子理论(E=1.24/λ)的计算结果相吻合,其发光强度随烧结温度的升高而增强;观察到了Tb^(3+)在Y_3Al_5O_(12)中的浓度猝灭现象。
Ab Using acrylamide （CH2 =CHCONH2 ） to form long chains of polyacrylamide and a cross-linker N＇,N＇-methylenebisacrylamide （CH2 =CHCONHCH2NHCOCH =CH2 ） to achieve tangled network, hydro- gen peroxide （ H2 02 ） as initiator and N, N, N＇, N＇-tetramethylethylenediamide [ （ CH3 ） 2 NCH2 CH2 N （ CH3 ） 2 ] as activator, we have successfully prepared the precursor from nitrates （ aluminum nitrate, yttrium nitrate, and terbium nitrate）, the precursor was subsequently heat-treated from 700 ℃ to 1 400 ℃ for 4 h to form terbium- doped yttrium aluminum garnet （ YAG： Tb^3＋ ） phosphor powders. The synthesized powders were characterized by thermogravimertry-differential thermal analysis （ TG-DTA）, X-ray diffraction （ XRD）, scanning electron microscopy （SEM） and fluorescence spectrometer. XRD analysis demonstrated that phase-pure YAG was obtained directly from the precursor at 850℃, without the formation of any intermediate phase （s） of YAP （YAlO3 ） and/or YAM （YAl4O9 ）. SEM images showed the particles were uniform, and the grain size increased with a rise in heat-treating temperature. The excitation spectrum consisted of three peaks with the highest intensity at 272 nm, the second at 230 nm and the third at 324 nm, respectively, all corresponding to the Tb^3＋ 4f-5d absorption. ^5 D4-^7Fj （j = 6,5,4,3 ） emissions were also observed clearly, the highest emission peaked is at 541.8 nm for the ^5D4-^7F5 transition of Th^3＋, the second is for the ^5D4-^7F6 with two lines at 486 nm and 490 nm, and the weaker emission from about 570 nm to 630 nm was corresponding to the transitions of ^5 D4-^ 7 F4 and ^5D4-^7F3 Enhanced luminescence intensity could be obtained by rising the sintering temperature which may improve the crystallization of YAG particles and favor the doping of Th^3＋ ions into YAG lattices. Concentration quenching phenomenon appeared when Th^3＋ molefraction （value of x ） in （Y1-xTbx）3Al5O12 is over 0.06.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第5期710-714,共5页
Chinese Journal of Luminescence
