Zheng Xuegang, Chen Ying, Liu Meijuan, Pan Shusheng, Liu Zhiyu, Xu Dekang, Lin Hao
School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, P. R. China.
Research Center for Advanced Information Materials, Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, P. R. China.
Phys Chem Chem Phys. 2023 Jul 26;25(29):19923-19931. doi: 10.1039/d3cp01440a.
The development of Tm 807 nm first near-infrared (NIR-I, 700-1000 nm) emission with second near-infrared (NIR-II, 1000-1700 nm) excitation is urgently needed, due to its potential application in biomedicine. In this work, a range of NaErF:Yb@NaYF:Yb@NaYF:Yb,Tm@NaYF multilayer core-shell structure upconversion nanoparticles (UCNPs) were successfully prepared by a co-precipitation method. The strongest UC emissions can be obtained by changing the concentration of Yb in the core and the first shell, and the proposed UC process was discussed in detail. The analysis shows that high-intensity NIR-I emission (807 nm) from Tm and visible light from Er were achieved through the energy migration among Yb and the energy back transfer from Yb to Er under 1532 nm excitation. Besides, compared to bilayer UCNPs, multilayer core-shell UCNPs display superior optical performance. The high-intensity NIR-I emission at 807 nm (Tm:H → H) under 1532 nm NIR-II excitation demonstrates huge advantages in bioimaging.
由于其在生物医学中的潜在应用，迫切需要开发在近红外二区（NIR-II，1000 - 1700 nm）激发下产生807 nm近红外一区（NIR-I，700 - 1000 nm）发射的材料。在这项工作中，通过共沉淀法成功制备了一系列NaErF:Yb@NaYF:Yb@NaYF:Yb,Tm@NaYF多层核壳结构的上转换纳米粒子（UCNPs）。通过改变核层和第一层壳层中Yb的浓度，可以获得最强的上转换发射，并对提出的上转换过程进行了详细讨论。分析表明，在1532 nm激发下，通过Yb之间的能量迁移以及Yb向Er的能量反向转移，实现了Tm的高强度近红外一区发射（807 nm）和Er的可见光发射。此外，与双层UCNPs相比，多层核壳UCNPs表现出优异的光学性能。在1532 nm近红外二区激发下807 nm处的高强度近红外一区发射（Tm:H → H）在生物成像中显示出巨大优势。
