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Updated: Apr 27, 2026
Synthesis of Core-shell Lanthanide-doped Upconversion Nanocrystals for Cellular Applications
Published on: November 10, 2017
Lanthanide-doped Sr2YF7 nanoparticles: controlled synthesis, optical spectroscopy and biodetection
Yuhan Yang1, Datao Tu, Wei Zheng
1Key Laboratory of Optoelectronic Materials Chemistry and Physics, and Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
Tetragonal-phase Sr2YF7 nanoparticles doped with trivalent lanthanide ions were synthesized for upconversion and downshifting luminescence. Shell coating enhanced luminescence, and these nanoprobes show potential for sensitive bioprobes in cancer diagnosis.
Area of Science:
- Materials Science
- Nanotechnology
- Luminescence
Background:
- Strontium yttrium fluoride (Sr2YF7) is a promising host matrix for trivalent lanthanide (Ln(3+)) ions.
- Lanthanide-doped phosphors are crucial for applications in lighting, displays, and bioimaging.
- Research on Sr2YF7 as a host for Ln(3+) luminescence, particularly for upconversion (UC) and downshifting (DS) properties, remains limited.
Purpose of the Study:
- To synthesize monodisperse, size-controllable tetragonal-phase Ln(3+)-doped Sr2YF7 nanoparticles (NPs).
- To investigate the upconversion (UC) and downshifting (DS) luminescence properties of these NPs.
- To evaluate the potential of these NPs as bioprobes for detecting specific biomarkers.
Main Methods:
- Facile thermal decomposition method for synthesizing Ln(3+)-doped Sr2YF7 NPs.
- Surface coating with an inert Sr2YF7 shell to enhance luminescence.
- Characterization of UC and DS luminescence properties upon 980 nm excitation.
- Application as heterogeneous time-resolved photoluminescence bioprobes.
Main Results:
- Monodisperse tetragonal-phase Ln(3+)-doped Sr2YF7 NPs were successfully synthesized.
- UC luminescence intensities were significantly enhanced (∼22 and 4 times for Tm(3+) and Er(3+), respectively) after shell coating.
- Intense multicolor DS luminescence was achieved with high absolute quantum yields (55.1% for Tb(3+), 11.2% for Eu(3+)).
- Luminescence lifetimes of Tb(3+) and Eu(3+) were measured as 3.7 ms and 8.1 ms, respectively.
- Demonstrated sensitive detection of avidin and carcinoembryonic antigen (CEA) with low limits of detection (40.6 pM and 94.9 pM).
Conclusions:
- The facile synthesis method yields high-quality Ln(3+)-doped Sr2YF7 NPs.
- Shell coating is an effective strategy to boost UC luminescence efficiency.
- These Sr2YF7:Ln(3+) NPs exhibit excellent DS luminescence properties.
- The long-lived luminescence and high sensitivity make these NPs promising for time-resolved luminescence bioprobes in cancer diagnosis.
