构建NaYF_(4):Yb^(3+)/Ho^(3+)/Ce^(3+)@NaYF_(4):Yb^(3+)/Nd^(3+)纳米核壳结构增强Ho^(3+)离子的上转换红光发射  

Enhancing red upconversion emission of Ho^(3+)ions through constructing NaYF_(4):Yb^(3+)/Ho^(3+)/Ce^(3+)@NaYF_(4):Yb^(3+)/Nd^(3+)core-shell structures

作　　者：董军 张晨雪 程小同 邢宇 韩庆艳 严学文 祁建霞 刘继红 杨祎 高伟 Dong Jun;Zhang Chen-Xue;Cheng Xiao-Tong;Xing Yu;Han Qing-Yan;Yan Xue-Wen;Qi Jian-Xia;Liu Ji-Hong;Yang Yi;Gao Wei(School of Electronic Engineering,Xi’an University of Post&Telecommunications,Xi’an 710121,China)

机构地区：[1]西安邮电大学电子工程学院,西安710121

出　　处：《物理学报》2021年第15期145-155,共11页Acta Physica Sinica

基　　金：陕西省国际交流项目(批准号:2019KW-027);陕西省自然科学基金(批准号:2019JQ-864);陕西省重点研发项目(批准号:2020GY-101,2020GY-127);西安市科技创新人才企业项目(批准号:2020KJRC0107,2020KJRC0112);西安邮电大学联合示范工作站项目(批准号:YJGJ201905)资助的课题.

摘　　要：三阶Ho^(3+)离子的红光发射位于生物组织的“光学窗口”中,在生物医学领域具有巨大应用前景,增强其红光发射已成为大家关注热点.为此,本文借助外延生长技术构建NaYF4:Yb^(3+)/Ho^(3+)/Ce^(3+)@NaYF4纳米核壳结构,并在其外壳中引入不同浓度的敏化离子Yb^(3+)和Nd^(3+)离子,以构建新的能量传递通道,实现Ho^(3+)离子的上转换红光发射增强.实验结果表明:在近红外光980 nm及800 nm激发下,NaYF4:Yb^(3+)/Ho^(3+)/Ce^(3+)@NaYF4:Yb^(3+)和NaYF4:Yb^(3+)/Ho^(3+)/Ce^(3+)@NaYF4:Yb^(3+)/Nd^(3+)核壳纳米结构均可实现Ho^(3+)离子的红光发射增强,最高可增强6.1倍,主要是由于外壳中的敏化离子可传递更多的激发能给Ho^(3+)离子.同时,研究发现在双波长(980 nm+800 nm)共激发下,NaYF4:20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF4:15%Yb^(3+)/20%Nd^(3+)核壳纳米晶体的红光发射强度明显高于两个单一波长激发下的红光发射强度及其之和,其原因是由双波长共激发的协同效应所致.由此可见,通过引入不同敏化离子构建多模式激发的稀土掺杂纳米核壳结构,不仅可实现上转换红光发射的增强及激发的有效调控,且可为进一步拓展该类材料在生物医学、防伪编码、多色显示等领域中的应用提供新思路.The red upconversion(UC)emission of Ho^(3+)ions is located in an“optical window”range of the biological tissue,which has great prospects in the biology application.In this work,the NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF_(4):x%Yb^(3+)and NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF_(4):15%Yb^(3+)/x%Nd^(3+)core-shell(CS)nanoparticles(NPs)are built based on the epitaxial growth technology by the high-temperature co-precipitation method in order to enhance red UC emission.The crystal structure and morphology of NaYF4 CS NPs are characterized by X-ray diffraction and transmission electron microscope.It can be found that the morphology of NaYF_(4) CS NPs changes from sphere into rod shape when coated with NaYF4 shell,and has a pure hexagonal-phase crystal structure.Under 980 nm excitation,the red UC emission intensity of NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF_(4):5%Yb^(3+)CS NPs is strongest and enhanced about 5.2 times than that of NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)NPs.Under 800 nm excitation,the red emission intensity of NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF_(4):15%Yb^(3+)/20%Nd^(3+)CS NPs is increased about 6.1 times compared with that of the NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF_(4):15%Yb^(3+)/5%Nd^(3+)CS NPs.This is because the constructed CS effectively reduces the non-radiative decay from the surface defects of NPs,and the doped Yb^(3+)and Nd^(3+)ions in the NaYF_(4) shells can transfer more excitation energy to Ho^(3+)ions in the core.In addition,the NaYF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaYF_(4):15%Yb^(3+)/20%Nd^(3+)CS NP is excited by dual-wavelengths co-excitation(800 nm+980 nm).It is found that the red UC emission intensity under the co-excitation of dual-wavelengths is higher than the sum of the excitation intensities of two single wavelengths(800 nm and 980 nm),which is due to the synergistic effect generated under the co-excitation of 980 nm and 800 nm near infrared laser.Therefore,different CS structures constructed by introducing different energy transfer cha

关 键 词：上转换红光发射 NAYF4 纳米晶体 核壳结构 双波长共同激发 

分 类 号：TB34[一般工业技术—材料科学与工程]