发光学报, 2016, 37 (9): 1056, 网络出版: 2016-11-23
3d5金属离子共掺杂NaYF4∶Yb,Er纳米晶的上转换发光
Upconversion Luminescence of NaYF4∶Yb,Er Nanocrystals Co-doped with 3d5 Metal Ions
上转换发光 过渡族离子 纳米核壳结构 能量传递 upconversion luminescence transition metal core-shell nanostructures energy transfer
摘要
采用水热法制备了Mn2+/Fe3+共掺杂的NaYF4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Fe3+共掺杂的上转换纳米晶为晶核, 通过改变反应时间来调控SiO2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。Mn2+/Fe3+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Fe3+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Yb3+-过渡族离子和Er3+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。
Abstract
Mn2+/Fe3+ 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 Mn2+ and Fe3+, respectively. In particular, the red emission of NaYF4∶Yb,Er,Fe nanocrystals was 7 times intensified selectively compared to the green band of Er3+. The intensified visible UCL especially the dominant red emission is mainly ascribed to the energy transfer from 2F7/2, 4T1g > (Yb3+-Mn2+/Fe3+ dimer) to 4F9/2 (Er3+) 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 3d5 metal ions.
唐静, 陈力, 谢婉莹, 刘玮洁, 黄宇欣, 李静, 张立功, 骆永石. 3d5金属离子共掺杂NaYF4∶Yb,Er纳米晶的上转换发光[J]. 发光学报, 2016, 37(9): 1056. TANG Jing, CHEN Li, XIE Wan-ying, LIU Wei-jie, HUANG Yu-xin, LI Jing, ZHANG Li-gong, LUO Yong-shi. Upconversion Luminescence of NaYF4∶Yb,Er Nanocrystals Co-doped with 3d5 Metal Ions[J]. Chinese Journal of Luminescence, 2016, 37(9): 1056.