Sensoric potential of gold-silver core-shell nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Optical Physics

Background:

• Localized surface plasmon resonance (LSPR) is sensitive to the surrounding refractive index.
• Core-shell nanostructures offer tunable optical properties for sensing applications.
• Previous studies utilized various nanostructures for refractive index sensing.

Purpose of the Study:

• To investigate the refractive index sensitivity of gold-silver core-shell nanoparticles.
• To determine the effect of shell thickness on LSPR sensitivity.
• To explore the potential for improving LSPR sensors.

Main Methods:

• Synthesis of gold-silver core-shell nanoparticles with varying shell thicknesses using a two-step chemical process without surfactants.
• Characterization of nanostructures using ultramicroscopy.
• Measurement of LSPR peak shifts in response to changes in the surrounding medium's refractive index.
• Theoretical calculations of optical properties for ideal and deformed core-shell nanoparticles.

Main Results:

• Gold-silver core-shell nanoparticles exhibited sensitivities comparable to or exceeding those of gold nanorods.
• An optimal silver shell thickness was identified, leading to significantly enhanced sensitivity.
• Theoretical calculations confirmed the experimental findings and explained the sensitivity enhancement through overlapping plasmon bands.
• The study demonstrated the potential for improving LSPR sensors by incorporating a specific metallic shell thickness.

Conclusions:

• Gold-silver core-shell nanoparticles are promising materials for refractive index sensing.
• Tailoring the silver shell thickness is crucial for maximizing LSPR sensor sensitivity.
• The findings suggest a viable strategy for developing next-generation LSPR-based sensors.