【作者】 郭庆捷；

【导师】 徐明霞；

【作者基本信息】 天津大学 ， 材料学， 2004， 硕士

【摘要】 本文以Al（OH）3为成核基体，以草酸为沉淀剂，以氨水调节反应液pH值，将Sr2＋、Eu3＋和Dy3＋均匀沉淀在Al（OH)3基体上，并在较低温度下制备了单相SrAl2O4:Eu，Dy长余辉发光材料。通过热分析和X射线衍射结果分析了SrAl2O4的结晶过程和相组成，并通过扫描电镜对粉体的微结构和表面形态进行了表征和分析，用荧光光谱仪测试及分析了工艺参数对粉体发光性能的影响，用屏幕亮度计测试了材料的余辉衰减曲线。 在采用包覆法制备前驱体时发现，前驱体的产率受沉淀剂和反应pH值的影响；铝酸锶结晶相在较低温度下由无定形态直接转化成结晶态，不生成氧化物的中间相，在较低温度下可合成SrAl2O4基质，比固相法降低100℃－150℃左右。研究发现随着Eu2＋离子浓度增大，SrAl2O4:Eu长余辉发光材料的发射强度随之增强，直到Eu2＋离子浓度超过2％mol时，其发射强度开始减小，Eu2+离子在SrAl2O4:Eu中的浓度猝灭包括两个不同的浓度猝灭过程。随着Eu2＋离子浓度增大，首先是中心Eu1向另一个中心Eu2传递能量而被猝灭，随后是发光中心Eu2发生自身的浓度猝灭。余辉衰减测试结果证实了SrAl2O4:Eu，Dy长余辉发光材料余辉衰减由初始的快衰减和其后的慢衰减两个过程所组成。SrAl2O4：Eu，Dy的余辉时间随着Dy3+离子浓度的增加而延长，当Dy3+掺杂浓度为2％时，余辉时间最长，当Dy3+浓度进一步增加时，余辉时间又会减少。硼酸的加入可有效的降低长余辉材料的煅烧温度，在一定范围内引入硼酸可促进SrAl2O4基质的形成，使发光材料的发光强度增大。硼酸含量过大则会使硼酸与包覆粉体表面的锶盐反应而形成硼酸锶盐，长余辉发光材料的发射带随着硼酸含量的增加会出现蓝移。更多还原

【Abstract】 This paper discussed the process of coated-precipitation for preparing SrAl2O4:Eu,Dy long afterglow photoluminescence materials. The Sr2+and rare earth ions were deposited on Al(OH)3 substrate by H2C2O4 as precipitator at pH value between 6～6.5 and at 40-45℃. The ratio of the precipitation of Eu3+ and Sr2+ was investigated by ICP , the phase compositions of precursor and production were analyzed by XRD, the particle morphology and grain diameter of the powders inspected by SEM, the uniformity of the coated precursor was examined by EDS, the processes of heat treatment were studied by the TG-DTA and XRD. Excitation and emission spectrum and decay characteristic of afterglow of the phosphor calcined with weak reducing atmosphere were investigated.The precipitator and pH value of solution affect the production effiency. strontium aluminates crystals were formed directly from amorphous state without any intermediate oxides crystals; the SrAl2O4 can be synthesized at low temperatures and the heating temperature is deduced by about 100 to 150 centigrade compared with the solid-state reaction. It is discoved that the emission intensity of phosphors increased firstly then decreased with the content of Eu2+ ions. The quenching concentration of the phosphors is 2mol% and the quenching mechanism is proved as dipole-dipole interaction. It is proved that the fluorescent decay process includes fast decay and consequently slow decay process due to the two different existent trapping levels. It was found that Dy3+ played an important role in the system resulted in different decay time.Influence of a little H3BO3 on reaction at high temperature and luminescent properties were investigated. It showed that phosphors can be calcined at lower temperature with a little H3BO3 added as flux.更多还原