Understanding metal-enhanced fluorescence and structural properties in Au@Ag core-shell nanocubes

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Gold-silver (Au@Ag) core-shell nanostructures exhibit localized surface plasmon resonance (LSPR).
• These structures are promising for catalysis, particularly oxygen reduction reactions (ORR), and as building blocks for self-assembly.
• Controlling the shell thickness is key to tuning their optical and catalytic properties.

Purpose of the Study:

• To fabricate Au@Ag core-shell nanocubes (Au@AgNCs) with tunable sizes and optical properties.
• To investigate the influence of silver shell thickness on the optical characteristics of Au@AgNCs.
• To explore the dual optical functions of Au@AgNCs in metal-induced fluorescence phenomena.

Main Methods:

• Facile synthesis of Au@AgNCs via stepwise silver reduction on gold nanoparticles (AuNPs).
• Structural characterization using Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and X-ray Diffraction (XRD).
• Measurement of metal-induced fluorescence properties of probe molecules during Au@AgNC sedimentation.

Main Results:

• Successfully fabricated Au@AgNCs with controllable size and optical properties by varying silver shell thickness.
• Demonstrated that Au@AgNCs possess tunable localized surface plasmon resonance (LSPR) properties.
• Observed dual optical functions: Au@AgNCs can act as fluorescence quenchers or enhancers depending on assembly.

Conclusions:

• Au@AgNCs are versatile building blocks with tunable optical properties.
• The size and optical characteristics of Au@AgNCs can be precisely modulated by controlling the silver shell thickness.
• The unique ring-like structure of Au@AgNCs enables dual fluorescence modulation capabilities, opening avenues for advanced optical applications.