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Insight into the Luminescence Alternation of Sub-30 nm Upconversion Nanoparticles with a Small NaHoF4 Core and
Ye Kuang1, Tianyao Li1, Tao Jia1
1Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, P. R. China.
Small (Weinheim an Der Bergstrasse, Germany)
|October 2, 2020
Summary
Researchers developed small core-multishell upconversion nanoparticles (UCNPs) with tunable colors and intensities. These advancements in NaHoF4@NaYbF4 (Ho@Yb) UCNPs enhance their potential for applications like photoinduced therapy.
Area of Science:
- Materials Science
- Nanotechnology
- Optics
Background:
- Upconversion luminescence (UCL) in highly doped upconversion nanoparticles (UCNPs) is crucial for material science development.
- Controlling UCL properties of UCNPs is essential for their specialized optical applications.
Purpose of the Study:
- To synthesize sub-30 nm core-multishell UCNPs (NaHoF4@NaYbF4) with tunable UCL properties.
- To investigate the impact of Gd3+/Yb3+ shell composition and layer variations on UCL.
- To explore the potential of these UCNPs for applications such as photoinduced therapy.
Main Methods:
- Synthesis of NaHoF4@NaYbF4 core-multishell UCNPs with varying Gd3+/Yb3+ ratios.
- Characterization using X-ray diffraction, transmission electron microscopy, UCL spectroscopy, and lifetime measurements.
- Analysis of pump power dependence to understand UCL mechanisms.
Main Results:
- Achieved tunable emission colors (red to yellow to green) and intensities by adjusting shell layers and Gd3+/Yb3+ concentrations.
- Demonstrated that surface energy loss and sensitizing energy supply, modulated by Gd3+ and Yb3+, are key determinants of UCL.
- Observed lowered UCL intensity and increased green/red ratio when Ho3+ was simultaneously doped into the shells.
Conclusions:
- Developed novel Ho@Yb UCNPs with precisely controlled UCL properties.
- Identified Gd3+ and Yb3+ modulation as critical for tuning UCL.
- Findings expand the application scope of NaHoF4 UCNPs, particularly for photoinduced therapy.
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