基质材料对Yb^(3+)浓度调控的上转换荧光红绿比的影响  

Effect of host matrix on Yb^(3+) concentration controlled red to green luminescence ratio

作　　者：张翔宇[1] 王丹 石焕文[1] 王晋国[1] 侯兆阳[1] 张力东 高当丽[2] Zhang Xiang-Yu;Wang Dan;Shi Huan-Wen;Wang Jin-Guo;Hou Zhao-Yang;Zhang Li-Dong;Gao Dang-Li(College of Science, Chang＇an University, Xi＇an 710064, China;College of Science, Xi＇an University of Architecture and Technology, Xi＇an 710055, China)

机构地区：[1]长安大学理学院,西安710064 [2]西安建筑科技大学理学院,西安710055

出　　处：《物理学报》2018年第8期106-114,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11604253;51771033);陕西省青年科技新星项目(批准号:2015KJXX-33);陕西省自然科学基金(批准号:2016JM5055);中央高校基本科研业务费(批准号:310812171004;301812172001);2017年省级大学生创新创业训练计划(批准号:1229);西安建筑科技大学本科生科研训练(SSRT)计划资助的课题~~

摘　　要：控制Yb^(3+)掺杂浓度是一种重要的调控红绿荧光比率的方法.然而,关于不同基质中Yb^(3+)浓度对红绿上转换荧光调控的敏感度仍缺少定量的对比研究,而且调控机理尚不清晰.本文通过乙二胺四乙酸辅助的水热法,合成了形貌可控的NaYF_4微米棒、LiYF_4微米八面体和YF_3微米砖三种氟化物晶体.通过激光共聚焦显微镜系统对比研究了Yb^(3+)/Er^(3+)掺杂的三种不同基质和形貌的单颗粒氟化物微米晶体的上转换荧光行为和红绿比率对Yb^(3+)变化的敏感度.研究结果表明:NaYF_4:Er^(3+)微米棒的红绿比率对Yb^(3+)的掺杂浓度响应最为敏感,各种Yb^(3+)浓度掺杂的LiYF_4:Er^(3+)微米八面体上转换荧光被绿光主控,而不同Yb^(3+)掺杂的YF_3:Er^(3+)微米砖表现出了稳定的黄光发射.通过分析荧光发射谱和比较上下转换荧光动力学过程结合荧光强度-功率依赖关系,基于拥有不同声子能量的基质辅助的Er^(3+)离子中间态的不同消布居途径,揭示了不同基质中红绿比率对Yb^(3+)变化响应的物理机制,并提供了一种研究上转换机理的思路.Rare earth doped upconverting micro/nanoparticles with controlled size and structure, which are excited by nearinfrared light and emit the visible light, possess many applications especially in the areas of biomedicine and photonics devices. There is no universally favored spectral profile in a variety of specific applications. We expect upconversion（UC） nanoparticles with the tunable spectral behavior to meet the demand for actual applications. Although the UC emission wavelengths are strictly limited by the electronic structure of the dopant, the spectral profile could be varied by many factors such as the structure, size, and crystallization. Varying matrix host is the most convenient approach to dynamically tuning UC that is essential for a variety of studies. However, this approach suffers a significant constraint due to insensitive response of most dopant luminescence centers to matrix host. In this paper, a facile EDTA-assisted hydrothermal approach is developed to the shape-selective synthesis of fluoride microcrystals including NaYF_4 rods,LiYF_4 octahedrons, and YF_3 cuboid brick, by only tuning the pH of the mother liquid. The UC spectra of a series of Yb^（3＋）/Er^（3＋）-doped fluoride particles with the different shapes and phases are investigated in detail under a near-infrared co-focused laser excitation. The effects of matrix hosts on UC luminescence attributed to the 4 f-4 f transitions of the Er^（3＋） ions in a single particle are amplified through elevating Yb^（3＋） concentration. The associated tuning mechanisms are explored by using the power dependent UC luminescence and the temporal evolutions of up/down-conversion emission spectra. Mechanistic investigation reveals that the sensitive response of Er^（3＋） UC emission to matrix host stems from maximal use of the various channels populated luminescence levels. It is well known that the population and depopulation of the luminescence levels strongly depend on the excitation power density, the energy level structure o

关 键 词：红绿比率 光谱调控 基质材料 Yb3+浓度 

分 类 号：TQ422[化学工程]