毕业设计-er3+yag上转换发光增强机制研究.docVIP

学科分类号 140 黑龙江科技大学 本科学生毕业论文 题 目 Er3+:YAG上转换发光增强机制研究 The Enhancement Mechanism Research of Er3+: YAG 姓 名 学 号 院 （系） 专业年级 指导教师 2015年6月24日 摘 要 由于稀土上转换发光材料具有很强的实用性，近年来倍受人们的关注。但是上转换发光材料的发光效率较低，限制了其应用。因此，如何提高稀土离子的上转换发光效率，扩大其应用领域成为研究的热点。影响稀土离子上转换发光效率的两个主要因素是：由于跃迁选择定则而造成的4f组态内能级之间禁戒的电偶极跃迁，以及由于基质材料的高声子能量而造成的无辐射跃迁。因此，增大电偶极跃迁几率，同时减弱无辐射跃迁几率可以提高发光效率。 Li+离子半径较小，掺杂Li+离子后可以降低基质材料的晶体场对称性。同时，由于Li+离子具有助烧剂作用，能够提高晶体的结晶度减少基质表面吸附的CO32-和OH-高能振动基团。在Er3+:YAG中掺杂Li+离子后，Er3+离子发光强度有了明显增加。绿光和红光最大增强倍数分别达到未掺杂Li+离子时的36和24倍。掺杂Li+离子不仅可以提高稀土离子的辐射跃迁几率，同时可以减少能级间的无辐射跃迁几率。掺杂Li+离子可以有效提高Er3+离子发光强度。 关键词：Li+离子掺杂；上转换发光；无辐射跃迁；稀土离子 Abstract As the rare-earth up-conversion luminescence material has a strong application background it has attracted more attention recent years.?However, the luminescence efficiency of the up conversion luminescence material is lower, which limits its application. Therefore, how to improve the efficiency of the rare earth ions, expand its application areas or become a research hot spot.?There are two main factors impacting on the conversion efficiency of rare earth ion: the transition selection rules caused by the energy levels within the 4f configuration of the electric dipole transition between the forbidden and the matrix material as a result of energy sub-loud non-radiative transition.?Therefore, increasing the electric dipole transition probability, and reducing non-radiative transition probability can increase the luminous efficiency.? As?the ionic radius of Li+ is small, Li+ ions doping can reduce the matrix material of the crystal field symmetry. Meanwhile, because the Li+ ion plays a sintering agent role, it can improve the crystallinity of the cr