Lifetime Manipulation by Excitation Power in Lanthanide Core-Shell Nanocrystals Without Altering Composition

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Fluorescence lifetime is crucial for optical multiplexing and applications.
• Current methods for lifetime adjustment require altering fluorophor content.

Purpose of the Study:

• To demonstrate excitation power-dependent fluorescence lifetime control in core-shell nanocrystals.
• To explore novel anti-counterfeiting patterns using tunable lifetime properties.

Main Methods:

• Synthesis of β-NaYbF₄:Er@NaYbF₄:Nd core-shell nanocrystals.
• Investigation of 1532 nm emission lifetime dependence on excitation power.
• Perturbed-population-dynamics calculations to confirm multiphoton processes.

Main Results:

• Achieved excitation power-dependent fluorescence lifetime in unaltered nanocrystals.
• Demonstrated dynamic, multidimensional anti-counterfeiting patterns using a single nanocrystal type.
• Confirmed nonlinear multiphoton process and nonradiative relaxation influence on emission.

Conclusions:

• Variable fluorescence lifetime in unaltered nanoparticles is achievable via multiphoton processes.
• This finding enables novel photonic nanomaterials for optical communication, sensing, and computing.
• Opens new avenues for dynamic optical information encoding and security.