Confining Excitation Energy in Er3+‐Sensitized Upconversion Nanocrystals through Tm3+‐Mediated Transient Energy Trapping

A new class of lanthanide‐doped upconversion nanoparticles are presented that are without Yb3+ or Nd3+ sensitizers in the host lattice. In erbium‐enriched core–shell NaErF4:Tm (0.5 mol %)@NaYF4 nanoparticles, a high degree of energy migration between Er3+ ions occurs to suppress the effect of concen...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2017-06, Vol.56 (26), p.7605-7609
Main Authors: Chen, Qiushui, Xie, Xiaoji, Huang, Bolong, Liang, Liangliang, Han, Sanyang, Yi, Zhigao, Wang, Yu, Li, Ying, Fan, Dianyuan, Huang, Ling, Liu, Xiaogang
Format: Article
Language:English
Subjects:
Biological effects
Coating effects
Confining
Crystals
Energy
energy migration
Er3+ sensitizers
Erbium
Excitation
I.R. radiation
Luminescence
Migration
Nanocrystals
Nanoparticles
Near infrared radiation
optical imaging
Quenching
transient energy trapping
Trapping
Upconversion
upconversion nanocrystals
Wavelengths
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Summary:A new class of lanthanide‐doped upconversion nanoparticles are presented that are without Yb3+ or Nd3+ sensitizers in the host lattice. In erbium‐enriched core–shell NaErF4:Tm (0.5 mol %)@NaYF4 nanoparticles, a high degree of energy migration between Er3+ ions occurs to suppress the effect of concentration quenching upon surface coating. Unlike the conventional Yb3+‐Er3+ system, the Er3+ ion can serve as both the sensitizer and activator to enable an effective upconversion process. Importantly, an appropriate doping of Tm3+ has been demonstrated to further enhance upconversion luminescence through energy trapping. This endows the resultant nanoparticles with bright red (about 700‐fold enhancement) and near‐infrared luminescence that is achievable under multiple excitation wavelengths. This is a fundamental new pathway to mitigate the concentration quenching effect, thus offering a convenient method for red‐emitting upconversion nanoprobes for biological applications. Contain your excitement: Core–shell design strategies are usually unable to prevent luminescence quenching caused by energy losses at lattice defects residing inside a nanocrystal. Through Tm3+‐mediated transient energy trapping, Er3+‐sensitized nanocrystals (NaErF4:Tm@NaYF4) displaying highly efficient upconversion emission are presented. These nanomaterials are capable of generating red and NIR emissions under multiple excitation wavelengths.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201703012