新型锂硅酸盐余辉发光材料的合成与余辉机理

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

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新型锂硅酸盐余辉发光材料的合成与余辉机理:http://www.youerw.com/cailiao/lunwen_67839.html