核-壳结构SiO_2@SrAl_2Si_2O_8∶Eu^(2+)粒子的制备及其性能

Synthesis and Luminescence Properties of Mono-disperse Spherical SiO_2@SrAl_2Si_2O_8∶Eu^(2+) Particles with Core-shell Structure

采用溶胶-凝胶法制备了核-壳结构SiO2@SrAl2Si2O8∶Eu2+粒子.经1000℃煅烧,在粒径约为350~400nm的单分散SiO2微球表面包覆了一层SrAl2Si2O8∶Eu2+.分别以X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、光致发光(PL)对合成产物进行了表征.XRD结果表明,SrAl2Si2O8∶Eu2+包覆层为六方相结构;SEM分析表明,在进行包覆后,核-壳结构SiO2@SrAl2Si2O8∶Eu2+粒子仍然呈良好的单分散状态;TEM分析表明,核-壳结构粒子存在明显的包覆层,其厚度约为20~30nm;激发和发射光谱测试表明,Eu2+有效地掺入了SrAl2Si2O8基质中,并具有良好的发光性能,SiO2@SrAl2Si2O8∶Eu2+的激发光谱峰值在361nm,发射光谱峰值在441nm,为Eu2+5d-4f跃迁.

Nanocrystalline SrAl2Si2O8∶Eu2＋ phosphor layers were coated on non-aggregated,mono-dispersed,and spherical SiO2 particles by sol-gel process at relatively low temperature,resulting in the formation of core-shell SiO2@SrAl2Si2O8∶Eu2＋ particles.X-ray diffraction,scanning electron microscope（SEM）,transmission electron microscope（TEM）,as well as photoluminescence were utilized to characterize the core-shell structured SiO2@SrAl2Si2O8∶Eu2＋ particles.XRD analysis confirms the formation of SiO2@SrAl2Si2O8∶Eu2＋ particles,it indicates that the SrAl2Si2O8∶Eu2＋ phosphor layers coated on SiO2 particles are hexagonal crystal phase.SEM and TEM indicate that the roughness of the SiO2 particles＇ surface obviously increases.The obtained core-shell phosphors consist of well dispersed submicron spherical particles with a narrow size distribution,and the thickness of coated layers is about 20-30nm.The core-shell particles show strong blue emission,which is ascribed to transition from 5d to 4f（around 440nm） of Eu2＋ under the excitation of ultraviolet light（361nm）.The excitation and emission spectra show that Eu2＋ can be incorporated into SrAl2Si2O8 effectively.The study of optical properties suggest that these particles may be used in plasma display panel（PDP） device and other luminescent apparatus.