3d^5金属离子共掺杂NaYF4:Yb,Er纳米晶的上转换发光  

Upconversion Luminescence of NaYF_4:Yb,Er Nanocrystals Co-doped with 3d^5 Metal Ions

作　　者：唐静[1] 陈力[1] 谢婉莹[1] 刘玮洁[1] 黄宇欣[1] 李静[1] 张立功[2] 骆永石[2] 

机构地区：[1]长春工业大学化学与生命科学学院,化学工程学院,材料科学高等研究院,基础科学学院,吉林长春130012 [2]发光学及应用国家重点实验室,中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《发光学报》2016年第9期1056-1065,共10页Chinese Journal of Luminescence

基　　金：国家自然科学基金(11474015,11504029);吉林省教育厅2015科研规划资助项目

摘　　要：采用水热法制备了Mn^(2+)/Fe^(3+)共掺杂的NaYF_4上转换纳米晶,通过改变掺杂浓度来调控晶相、晶粒尺寸以及上转换荧光发射强度。以Fe^(3+)共掺杂的上转换纳米晶为晶核,通过改变反应时间来调控SiO_2壳厚度,观察到上转换荧光发射强度在反应4 h的条件下出现最大值。Mn^(2+)/Fe^(3+)共掺杂的上转换纳米晶样品整体上转换荧光强度分别提高到3.7倍和4.5倍,同时Fe^(3+)共掺样品的红色上转换荧光增强近7倍。基于近红外980 nm激光激发下的稳态光谱研究,提出Yb^(3+)-过渡族离子和Er^(3+)之间的能量传递以及晶场对称性的改变引起了这种增强效应,随着过渡族离子掺杂浓度的增加,过渡族离子之间的交换相互作用导致上转换荧光的猝灭。Mn^2＋/ Fe^3＋ co-doped upconverting nanocrystals were prepared by hydrothermal method.The crystal phase,size and fluorescence intensity were modulated via changing the doping concentrations. The maximum intensity of upconversion luminescence（ UCL） was observed in current work at the reaction time of 4 h when coating the silica shell of different thickness onto the NaYF4∶ Yb,Er,Fe nanocrystals through facilely altering the reaction time. The integrated overall intensity of upconversion luminescence was 3. 7 and 4. 5 times enhanced by co-doping Mn^2＋ and Fe^3＋ ,respectively. In particular,the red emission of NaYF4∶ Yb,Er,Fe nanocrystals was 7 times intensified selectively compared to the green band of Er^3＋ . The intensified visible UCL especially the dominant red emission is mainly ascribed to the energy transfer from ｜~2F（7/2）,~4T（1g）（ Yb^3＋ -Mn^2＋/ Fe^3＋ dimer） to ~4F（9 /2）（ Er^3＋ ） states as well as the distortion of the crystalline field symmetry. The quenching of UCL as increasing dopants is stemming from the exchange interaction between 3d^5 metal ions.

关 键 词：上转换发光 过渡族离子 纳米核壳结构 能量传递 

分 类 号：O482.31[理学—固体物理]