Improved Upconversion Luminescence in Water-Soluble Yb3+/Er3+ Codoped LaF3 Nanoparticles Through Ca2+ Doping

Area of Science:

• Materials Science
• Nanotechnology
• Luminescence

Background:

• Lanthanum fluoride (LaF3) nanocrystals doped with ytterbium (Yb3+) and erbium (Er3+) are investigated for their luminescent properties.
• Controlling nanocrystal size, solubility, and luminescence intensity is crucial for practical applications.

Purpose of the Study:

• To synthesize monodisperse, water-soluble LaF3: Yb3+/Er3+ nanocrystals using an eco-friendly method.
• To investigate the effect of calcium (Ca2+) doping on the upconversion luminescence of these nanocrystals.

Main Methods:

• A fast, facile, and environmentally-friendly polyol process was employed for nanocrystal synthesis.
• Polyvinylpyrrolidone (PVP) was used as an amphiphilic surfactant to ensure water solubility and dispersion.
• Ca2+ doping was introduced to modify the crystal structure and luminescence properties.

Main Results:

• Monodisperse LaF3: Yb3+/Er3+ nanocrystals with an average size of 18 nm were successfully synthesized.
• The nanocrystals exhibited good dispersibility in hydrophilic solutions.
• Ca2+ doping led to an enhanced upconversion luminescence intensity, attributed to reduced symmetry around the rare earth ions.

Conclusions:

• The polyol process provides an efficient route for fabricating water-soluble LaF3: Yb3+/Er3+ nanocrystals.
• Ca2+ doping is an effective strategy to boost the upconversion luminescence of these nanomaterials.
• The developed nanocrystals show potential for applications requiring efficient luminescence in aqueous environments.