摘要
论文综述了各种长余辉发光材料的发展历史和研究现状。长余辉发光材料中长余辉发光玻璃具有非常广阔的应用前景,可以应用于激光、光学放大器、光通讯、储能和显示等诸多领域。深入开展高性能长余辉玻璃的研究和应用开发具有重要的意义。
本文旨在研究基质玻璃组成对Tb~(3+)掺杂ZnO-B_2O_3-SiO_2(ZBS)长余辉玻璃荧光性质、余辉性能、光致变色和热褪色等性质的影响规律,从而分析和探讨ZBS:Tb~(3+)玻璃的长余辉发光机理,同时开展一些掺杂ZBS玻璃陶瓷的探索性研究,以期寻求更好的基质玻璃组成和制备出性能优良的长余辉玻璃陶瓷材料。
通过荧光光谱、余辉衰减曲线、热释光谱以及紫外-可见吸收光谱系统地研究了不同基质组成的Tb~(3+)掺杂ZBS长余辉玻璃的荧光性质、余辉特性、光致变色和热褪色现象。基质中ZnO含量对玻璃的余辉性能和光致变色具有很大的影响,研究表明:ZnO含量的提高并没有在基质玻璃中形成新的陷阱,而是增加了玻璃基质中与Zn离子相关的氧空位陷阱的浓度;在紫外光照射后,不同陷阱能级深度的色心的浓度也相应增加;这些色心中能级深的色心将稳定存在于基质中,导致光致变色,陷阱能级浅的色心引起长余辉,所以随着ZnO含量的提高,玻璃中Tb~(3+)的~5D_4→~7F_5跃迁对应的余辉发光初始强度增大、寿命变长,同时光致变色程度增大。在紫外光激发下,存在ZBS基质玻璃向发光离子Tb~(3+)的能量传递,传能效率随着ZnO含量的提高而减小,ZnO含量大于65mol%后几乎不再有传能。SiO_2含量的提高使ZBS玻璃的荧光强度有所增加,对余辉性能影响不大。结合已有机理和实验分析,我们认为Tb~(3+)掺杂的ZnO-B_2O_3-SiO_2玻璃中的长余辉可能来自于被俘获电子和光氧化的发光离子的热助隧道复合过程。
分析测试了单掺Tb~(3+)以及Mn~(2+)的ZBS玻璃在析晶热处理过程中的光谱变化规律,结果表明这种未掺晶核剂的玻璃的不可控析晶过程会导致样品的荧光强度有所降低,激发和发射峰位未出现位移。研究了析晶过程对共掺晶核剂TiO_2和发光离子的ZBS玻璃的荧光性质的影响。研究表明:共掺Tb~(3+),TiO_2的ZBS玻璃在紫外光激发时主要表现出Tb~(3+)的特征发射,同时也有Ti~(3+)的宽带发射;随着玻璃析
浙江大学硕士毕业论文
晶过程的进行,Tb3+周围配位场的变化导致Tb3‘的发光量子效率不断提高,荧光
强度持续增加;共掺MnZ‘,TIOZ的ZBS玻璃在紫外光激发时表现出中心波长为
51Onm宽带荧光发射,强度随着析晶程度的增加而增大。
This thesis reviews the history of long-lasting phosphorescent materials comprehensively and presents its recent progress. Long-lasting phosphorescent glass has very wide application and can be used in the fields of laser, optical amplifier , optical communication, energy storage, display etc. It is very useful to carry out the research of high-quality long-lasting phosphorescent glasses.
The influence of composition in the host glass on spectra, long-lasting phosphorescent property, photochromism and heat-bleaching property was studied.
The phosphorescence mechanism of ZBS: Tb glass was discussed based on the study. At the same time the tentative study of Tb3+, Mn2+ doped ZBS glass ceramics was also carried out. The research was aimed to find the proper host glass and prepare the long-lasting phosphorescent glass ceramics with high quality.
The spectra, long-lasting phosphorescent property, photochromism and heat-bleaching property of ZBS: Tb3+ glass with different host composition was systematically investigated by photoluminescence spectra, luminescence decay curves, thermo-luminescence spectra and UV-visible absorption spectra etc. The content of ZnO in the host glass had manifest influence on long-lasting phosphorescent property and photochromism of glass. The research indicates: the increase of ZnO content didn't lead to the formation of new defects but add to the concentration of oxygen ion vacancy associated with Zn2+. After UV-illumination irradiation the concentration of color centers with different depth increased accordingly. Those color centers at deep depth will be stable and mainly responsible for color change, those with shallow depth attribute to the long-lasting luminescence. The intensity and time of afterglow corresponding to 5D4->7F5 transition of Tb3+ were found to be increased with increasing ZnO content. The energy was tr
ansferred from the host glass to Tb3+ when the glass was irradiated by UV- illumination. The efficiency of energy-transfer decreased with the increasing of ZnO content and the energy-transfer diminished when the ZnO content was more than 65mol%. The content of SiO2 in the host glass
had slightly influence on long-lasting phosphorescent property of glass.
Both the spectra changing character of ZBS glass doped with Tb3+ and that doped with Mn2+ during the heat treatment were investigated, which indicated that the uncontrolled crystallization process would not only result in the weakening of the luminescence intensity but also lead to the displacement of the position of the excitation and emission peaks. Additionally, the influence of crystallization process on the luminescence behavior of Tb + and TiO2 co-doped ZBS glass was also studied, showing that when this kind of glass was excited by ultraviolet, the characteristic spectrum of Tb3+ ion as well as the broad-band emission spectrum of Ti3+ would appear, with the former more manifest than the latter, and that the changing of crystal field of Tb3+ ion would consistently improve the quantum efficiency, companied with the increase of the luminescence intensity of the glass; Besides, it was also shown that when excited by ultraviolet, the broad-band major emission peak of the co-doped glass at 510nm would occur,
the intensity of which was continuously increasing as the crystallization process went on.
引文
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