摘要在10%氢气气氛下通过高温固相反应得到新型的发绿色光的长余辉荧光粉Li2Ca0.4Sr0.6SiO4:Tb3+和橙黄色光的长余辉荧光粉Li2Ca0.4Sr0.6SiO4:Eu2+ ,Dy3+。测试该荧光粉的X射线衍射（XRD），光致发光光谱（PLS），长余辉光谱（LAS）和热释光谱（TLS）去表征其物理性质。Li2Ca0.4Sr0.6SiO4:Tb3+荧光粉的发射光谱得到Tb3+离子的5D4-7Fj跃迁，相应于X =0.3456，Y =0.5745 CIE色度坐标。Li2Ca0.4Sr0.6SiO4:Eu2+ ,Dy3+荧光粉的发射光谱为500-700nm的一个宽带发射，最高峰位于587nm对应于Eu2+的4f65d1-4f7的跃迁，对应x = 0.5368, y = 0.4593 CIE色度坐标。Tb3+的在基质中的最佳浓度确定为0.8％，Eu2+，Dy3+共掺杂的最佳浓度确定为7%和3%。当紫外线光源被关闭，Li2Ca0.4Sr0.6SiO4和Li2Ca0.4Sr0.6SiO4:Eu2+ ,Dy3+荧光粉呈典型的余辉的行为。在拟合实验数据后展现了一个典型的三重指数衰减行为。热释光的研究进一步表明，Li2Ca0.4Sr0.6SiO4:Tb3+荧光粉的余辉行为是由于稀土离子(Tb3+)掺杂Li2Ca0.4Sr0.6SiO4产生的空穴和电子复合产生的，Li2Ca0.4Sr0.6SiO4:Eu2+ ,Dy3+荧光粉的余辉性能的提高是由于Dy3+离子的加入导致陷阱浓度的增大。对于Li2Ca0.4Sr0.6SiO4:Tb3+和Li2Ca0.4Sr0.6SiO4:Eu2+ ,Dy3+的长余辉发光机理在实验结果的基础上进行了详细的讨论。61854

毕业论文关键词： Li2Ca0.4Sr0.6SiO4 ；固相反应；光学特性；长余辉；陷阱

Synthesis and afterglow mechanism of new lithium silicate afterglow luminescent material

Abstract：The novel green emitting long afterglow phosphor Li2Ca0.4Sr0.6SiO4:Tb3+ and the novel orange-yellow emitting long afterglow phosphor Li2Ca0.4Sr0.6SiO4:Eu2+, and Li2Ca0.4Sr0.6SiO4: Eu2+, Dy3+ were obtained via a high temperature solid-state reaction in air atmosphere. X-ray diffraction (XRD), photoluminescence spectroscope (PLS), long afterglow spectroscope (LAS) and thermal luminescence spectroscope (TLS) were performed to characterize the physical properties of the phosphors. Typical 5D4-7Fj transitions of Tb3+ ions were detected by PL spectra, corresponding to CIE chromaticity coordinates of x = 0.3456, y = 0.5745. Typical 4f65d1 → 4f7 transitions of Eu2+ ions were detected by PL spectra, revealing a broad and intensive emission extending from 500 to 700nm with a peak at about 587nm, corresponding to CIE chromaticity coordinates of x = 0.5368, y = 0.4593. An optimal concentration of Tb3+ in the substrate was determined as 0.8%. Optimal concentrations of Eu2+ and Dy3+ in the substrate were determined as 7at% and 3at%. The Li2Ca0.4Sr0.6SiO4 phosphors and the Li2Ca0.4Sr0.6SiO4: Eu2+, Dy3+ phosphors showed a typical afterglow behavior when the UV source was switched off. A typical triple exponential decay behavior was confirmed after fitting the experimental data. Thermal simulated luminescence study further indicated that the afterglow behavior of Li2Ca0.4Sr0.6SiO4:Tb3+ phosphors was generated by the recombination of electrons with the holes resulted from the doping of rare-earth ions (Tb3+) in Li2Ca0.4Sr0.6SiO4 host,and the enhancement of afterglow property of Li2Ca0.4Sr0.6SiO4:Eu2+,Dy3+ phosphors was due to the increasement of trap concentration resulting from the incorporation of Dy3+ ions. The long afterglow luminescence mechanism of Li2Ca0.4Sr0.6SiO4:Tb3+ and Li2Ca0.4Sr0.6SiO4:Eu2+, Dy3+ are illustrated and discussed in detail on the basis of experimental results.

Keywords: Li2Ca0.4Sr0.6SiO4 ；solid state reaction；Optical properties；Long afterglow； Traps

 目录

1. 绪论 1

1.1课题背景 1

1.2硅酸盐材料的简介 2

1.2.1传统硅酸盐体系长余辉发光材料 2

1.2.2硅酸盐体系长余辉发光材料的发展历史