【作者】 张丽平；

【导师】 熊光楠；

【作者基本信息】 天津理工大学 ， 凝聚态物理， 2004， 硕士

【摘要】 紫外线（UV）同可见光一样是一种电磁波。但是，紫外线的频率范围刚好高于可见光，其波长完全不在人类可视范围之内。紫外线根据其波长可分为三类：UV-A、UV-B和UV-C。UV-A（315nm＜λ＜400nm）几乎接近可见光，已广泛应用于生产和生活中；UV-B（280nm＜λ＜315nm）居中；UV-C的波长集中于254nm，具有杀菌作用。紫外光线的广泛应用，使得紫外光的荧光粉的研究也日益重要。在众多荧光粉中以稀土产生的波长最接近紫外光。本文探索性的研究了几种发紫外光的荧光材料，在材料本身的发光特性上作了研究。并在开发紫外荧光材料的应用上作了大胆性的设想——根据X射线增感屏可以使X光胶片增感这一理论。通过对制成IP的主要材料BaFBr∶Eu²⁺的光激励发光机理进行研究，采用紫外（UV）和真空紫外（VUV）光模拟荧光材料的发光，看哪个波段的光对IP起增感作用。为今后紫外荧光材料的应用开辟了新的方向。本论文的的主要研究内容：1、研究紫外发光材料LiXAlF₆∶Ce³⁺（X=Ca，Sr，Ba）、XBaAlF₆：Ce³⁺（X=Li，Na，K）、LiBaXF6：Ce³⁺（X=Al，Ga，In）的发光性质和Ce³⁺的掺杂浓度对发光的影响。Ce³⁺在LiXAlF₆（X=Ca、Sr、Ba）基质中的发光都在紫外区域，而且发光峰值各异。随着X元素原子序数的增大，Ce³⁺的发光峰向短波方向移动。首次研究了一价和三价离子对Ce³⁺发光的影响，发现基质中的一价和三价元素的变化不影响发射光谱的峰值，它们在晶格中起一个填隙和电荷补偿的作用，有利于Ce³⁺的发光。2、研究了在不同的激发波长下BaY₂F₈∶Er³⁺材料的发射光谱和发光性质。①首次研究了Er³⁺在BaY₂F₈基质中各个能级跃迁对发光的贡献。②首次利用电偶极和磁偶极跃迁计算了Er⁽3+_在BaY₂F₈中可能占据的格点位置与其跃迁特征。并完成了Er³⁺的电子能级跃迁在各波长激发下的发射光峰值的指认。3、分析总结了X光胶片增感屏增感的原理和各类增感屏的优、缺点。首次提出IP的增感，分析得出荧光增感法适合IP的增感。4、利用UV光和VUV光分别模拟了紫外光和真空紫外光对IP板的增感，得出了IP板在UV光和VUV光激发下的一些特性。①首次应用光电子和热电子与发光中心复合和被陷阱俘获几率的不同，在理论上对处于Eu²⁺的激发态电子遂穿模型作了定性的分析。②首次通过对经X射线辐照过的样品的光激励发光的监测，找出了真空紫外光对样品起增感作用的波段。更多还原

【Abstract】 Ultra violet （UV） light is a kind of electron magnetic waves as the visible light, but with higher frequency. It can be divided into UV-A, UV-B and UV-C according to its wavelength. The merits of UV light have been widely recognized and the study of UV phosphor has been fervently carried on.In this paper, several phosphors, which emission is located between UV, were studied, and the appliance of these phosphors was conceived. These phosphors can be used to intensify BaFBr:Eu²⁺, an excellent radiation storage phosphor. The intensifying effect was firstly simulated with UV and VUV as the emission of these phosphors. Creations obtained:The luminescent properties of LiXAlF₆:Ce³⁺（X=Ca, Sr, Ba） XBaAlF₆:Ce³⁺（X=Li, Na, K） and LiBaXF₆:Ce³⁺（X=Al, Ga, In） were studied. From that, we knew the emissions of these phosphors were all located in the UV region and the emission peaks were different. The effect of doped Ce³⁺ on the luminescence is also studied, the emission peaks of Ce³⁺ shift to shorter wavelength with the increasing of the nuclear number. The effect of mono-valent cations and tri-valent cations upon the emission of Ce³⁺ was firstly studied, it was suggested that the doped mono-valent cations and tri-valent cations do not affect the emission peak, they act as the effect of charge-compensate or blank-fill.The emission and excitation of BaY₂F₈:Er³⁺ were studied. It is the first time that the contribution of Er³⁺ on the transition of BaY₂F₈:Er³⁺ energy level was studied. And it is the first time that the occupied site and the transition properties of Er³⁺ were calculated by transition of electron-dipoles and magnetic-dipoles. The transition of electron energy level of Er³⁺ matches the emission peaks by the different excitation wavelength.After the discussion of the principles of intensifying screens for X ray fluorescent films, the intensifying on imaging plate was firstly proposed, and it was suggested that fluorescent intensifying manner is suitable to IP. UV and VUV light were used to simulate the intensifying effect of UV and VUV phosphor on IP. It is the first time to use the different possibility of photon-electrons and thermal-electrons by traps and luminescent centers to analyze the tunneling model of excited Eu²⁺ electrons. And it is the first time to find out the intensifying band in VUV region after the inspection of Eu³⁺ emission of X ray irradiated samples.更多还原