Enhanced Upconversion Luminescence in Yb³⁺/Tm³⁺-Codoped Fluoride Active Core/Active Shell/Inert Shell Nanoparticles...

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Lanthanide-doped upconversion nanoparticles (UCNPs) are crucial for biophotonics and photonics.
• Improving their luminescence efficiency is key for advanced applications.

Purpose of the Study:

• To enhance the upconversion luminescence efficiency of sodium yttrium fluoride (NaYF₄) nanoparticles doped with ytterbium (Yb³⁺) and thulium (Tm³⁺).
• To investigate the role of directed energy migration in a hierarchical core/shell nanostructure.

Main Methods:

• Fabrication of a hierarchical NaYF₄:Yb³⁺/Tm³⁺ active core/active shell/inert shell nanostructure.
• Utilizing directed energy migration within the active shell layer.
• Characterization of upconversion luminescence properties under ~980 nm excitation.

Main Results:

• Achieved an approximately 240-fold enhancement in upconversion luminescence.
• The hierarchical active core/active shell/inert shell UCNPs were ~11 times brighter than active core/inert shell UCNPs.
• Demonstrated the effectiveness of directed energy migration for luminescence enhancement.

Conclusions:

• The hierarchical active core/active shell/inert shell design significantly boosts UCNP brightness.
• Directed energy migration is a viable strategy for enhancing upconversion luminescence in Yb³⁺/Tm³⁺-codoped NaYF₄ nanoparticles.
• This approach holds potential for other lanthanide-doped UCNPs.