喷雾热解法制备SrAl₂O₄:Eu²⁺，Dy³⁺及其性能表征

【作者】 李敏；

【导师】 王林生；

【作者基本信息】 江西理工大学 ， 材料学， 2011， 硕士

【摘要】 本文综述了稀土离子激活的碱土铝酸盐蓄光材料的研究现状,特别是铕镝共激活的碱土铝酸锶长余辉材料的发展历程、研究现状、制备方法以及发光机理。采用喷雾热解法合成了球形SrAl₂O₄:Eu²⁺,Dy³⁺长余辉发光材料,研究了不同制备工艺条件对SrAl₂O₄:Eu²⁺,Dy³⁺发光材料的结构、形貌、粒度分布、余辉性能及光谱性能的影响,并与高温固相法所制备的SrAl₂O₄:Eu²⁺,Dy³⁺长余辉发光材料进行了对比。实验结果表明:采用高温固相法制备了SrAl₂O₄:Eu²⁺,Dy³⁺长余辉发光材料,SrAl₂O₄:Eu²⁺,Dy³⁺的晶体结构与ɑ-SrAl₂O₄磷石英晶体结构相同,掺杂Eu、Dy对晶体结构的影响很小。助熔剂硼酸的使用不但能降低合成温度,还能增强发光材料的余辉性能。硼酸用量的变化对SrAl₂O₄:Eu²⁺,Dy³⁺发射光谱特征峰位的影响不大。对于SrAl₂O₄:Eu²⁺体系的发光材料,其最佳辅助激活剂是Dy³⁺,Dy³⁺的引入能显著增强发光材料的余辉性能,但不会改变发射光谱的形状和特征峰位,当Eu²⁺与Dy³⁺的比值为0.01:0.02时,可获得余辉性能较好的SrAl₂O₄:Eu²⁺,Dy³⁺长余辉发光材料。高温固相法制备SrAl₂O₄:Eu²⁺,Dy³⁺的还原温度在1350℃,还原时间为3h时,可获得余辉性能较好的长余辉发光材料。采用喷雾热解两段法制备了球形SrAl₂O₄:Eu²⁺,Dy³⁺长余辉发光材料,SrAl₂O₄:Eu²⁺,Dy³⁺的晶体结构与ɑ-SrAl₂O₄磷石英晶体结构相同,掺杂Eu、Dy对晶体结构的影响很小。前驱体溶液浓度、热解温度和还原温度对产物的形貌、粒度分布、发光性能有较大影响。随着还原温度的升高,产物的发射主峰位置发生红移。助熔剂H₃BO₃的引入不但能降低合成温度,还能有效地提高发光材料的余辉性能,当硼酸的用量为3.5mol%时,可以形成较好的SrAl₂O₄晶体,且发光材料具有好的余辉性能和形貌。随着硼酸用量的增加,长余辉发光材料的激发光谱出现“蓝移”现象。添加剂的使用能明显改善和修饰材料的形貌、增强材料的初始亮度、延长材料的余辉时间（柠檬酸的使用会缩短材料的余辉时间）。柠檬酸的加入有助于获得实心球形颗粒,乙醇除了良好的分散性,还能有效的增大颗粒的球形度,但无法获得实心颗粒,PEG能够起到分散剂和稳定剂的作用。当三种添加剂同时使用时可获得初始亮度高、余辉时间长、分散性好、粒度小、粒径分布窄（2μm～5μm）的实心球形颗粒。它们的最佳加入量为:柠檬酸为0.3g/L;PEG为0.03mol/L;乙醇为40ml/L。喷雾热解法制备的SrAl₂O₄:Eu²⁺,Dy³⁺长余辉发光材料,较之高温固相法所制备的具有合成温度低、分散性好、粒度小、粒径分布窄（2μm～5μm）、形貌规则（实心球形）、发光亮度高、余辉时间长（>65h）等优点。更多还原

【Abstract】 In this paper,the development course,research status,preparation method and the emitting mechanism of rare earth ions actived alkaline aluminates salt light-storing materials,especially of SrAl₂O₄:Eu²⁺,Dy³⁺ long afterglow luminescence materials were summarized.The spherical SrAl₂O₄:Eu²⁺,Dy³⁺ was synthesized by a two-step spray pyrolysis process.The structure,morphology,luminous performances and Spectral properties of SrAl₂O₄:Eu²⁺,Dy³⁺ at different preparation technology conditions were studied.and compared with the preparation methods of solid state reaction at a high temperature.The results showed that:The SrAl₂O₄:Eu²⁺,Dy³⁺ prepared by solid state reaction at a high temperature belongs to theɑ-SrAl2O4 phosphor crystal structure . Small amount of Eu、Dy introduced into the mixture did not affect the crystal structure of SrAl2O4.The flux H3BO3 could not only reduce the synthesis temperature, but also enhance the afterlow performance. The shape of the emission spectrum of SrAl₂O₄:Eu²⁺,Dy³⁺ did not be changed by the use of flux H3BO3. Dy3+ was the best auxiliary activators for SrA12O4:Eu2+ luminescence materials, Dy3+ could enhance the afterlow performance and won’t change the peak location of its emission spectrum. The best composition of the prepared material with better afterlow performance was Sr0.97Al2O4:Eu0.01,Dy0.02. The SrAl₂O₄:Eu,Dy luminescence materials with better afterlow performance could be obtained by solid state reaction method when reduction temperature was 1350℃and reduction time was 3h .The SrAl₂O₄:Eu²⁺,Dy³⁺ prepared by spray pyrolysis belongs to theɑ-SrAl2O4 phosphor crystal structure and small amount of Eu、Dy introduced into the mixture did not affect the crystal structure of SrAl2O4. The morphology,size distribution and luminous performances of the phosphors could be affected with synthesizing conditions, such as precursor concentration, sintering temperature, reduction temperature etc. As the reduction temperature rised, red shift of the main peak position in the emission spectrum had occurred （move to longer wavelengths）.H3BO3 could not only reduce the synthesis temperature, but also enhance the afterlow performance.The SrAl₂O₄:Eu²⁺,Dy³⁺ with better crystals,good luminous performance and morphology was syshtesised when the adding quantity of H3BO3 was 3.5mol%.As the add amount of H3BO3 increased,（2.5mol%～5mol%）,the long afterlow material inspire spectra appear "blue shift" phenomenon.Additives caould obviously improve the morphology,reinforce the initial brightness,enlarge the afterlow time （citric acid would shorten the afterlow time）.Citric acid could help to obtain solid spherical particle. Ethanol was not only a good dispersant but also increased the sphericity of particle, howerve, solid spherical particles couldn’t be gotten in this condition. PEG played the role of dispersant and stabilizer. The solid spherical SrAl₂O₄:Eu²⁺,Dy³⁺ particles with high initial brightness, long twilight time, good dispersion, small particle size and narrow particle size distribution （2μm⁵μm） when these additives used at the same time.Their best addition amount were citric acid of 0.3g/L, PEG of 0.03mol/L, ethanol of 40ml/L.Compared with solid state method,the SrAl₂O₄:Eu²⁺,Dy³⁺ with more regular morphology,smaller particle size, narrower particle size distribution and more excellent luminescent properties could be prepared by spray pyrolysis, and the synthesis temperature can be significantly reduced.更多还原