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In-depth insight into the Yb3+ effect in NaErF4-based host sensitization upconversion: a double-edged sword
Yang Wang1, Shuai Zhou1, Fuyao Sun1
1School of Chemical Engineering, Nanjing University of Science and Technology, 210094, China. fujiajun668@gmail.com.
Nanoscale
|October 21, 2022
Summary
Ytterbium (Yb3+) doping in sodium erbium fluoride (NaErF4) nanocrystals has a complex effect on upconversion luminescence. While Yb3+ can enhance green emission in the core, it often weakens red emission in core-shell structures due to energy dissipation.
Area of Science:
- Materials Science
- Nanotechnology
- Luminescence
Background:
- Sodium erbium fluoride (NaErF4) is a key host for self-sensitized upconversion (UC).
- Ytterbium (Yb3+) is commonly used as an energy absorber in NaErF4 systems.
- The role of Yb3+ in NaErF4-based UC, particularly in core-shell structures, is complex and requires detailed investigation.
Purpose of the Study:
- To thoroughly investigate the effect of Yb3+ location (core vs. shell) on NaErF4-based host-sensitized UC.
- To elucidate the underlying mechanisms responsible for Yb3+'s influence on UC emissions.
- To explore the application potential of engineered NaErF4 nanocrystals.
Main Methods:
- Synthesis and characterization of NaErF4 core nanocrystals with varying Yb3+ concentrations.
- Fabrication of NaErF4:Yb core-inert shell nanocrystals.
- Investigation of NaErF4:Yb@NaYF4:Yb core-shell nanocrystals with varied shell Yb3+ doping.
- Analysis of upconversion luminescence (UCL) properties, including emission intensity and spectral characteristics.
Main Results:
- In NaErF4 core nanocrystals, increasing Yb3+ concentration enhanced green UCL due to improved energy harvesting.
- Core-inert shell nanoparticles showed emission intensity variations attributed to lattice mismatch and shell thickness.
- In NaErF4:Yb@NaYF4:Yb core-shell structures, red UCL generally weakened with increased shell Yb3+ doping, attributed to energy pooling and dissipation.
Conclusions:
- Ytterbium (Yb3+) acts as a 'double-edged sword,' exerting a dual influence on UC emissions in Er3+-based hosts.
- Understanding Yb3+ distribution is crucial for optimizing UC properties in core-shell nanocrystals.
- Engineered NaErF4 nanocrystals show promise for applications in water sensing and anti-counterfeiting.
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