Tailorable plasmonic circular dichroism properties of helical nanoparticle superstructures

Area of Science:

• Nanotechnology
• Materials Science
• Plasmonics

Background:

• Gold nanoparticles (AuNPs) are crucial in plasmonics due to their tunable optical properties.
• Self-assembly of nanoparticles offers a route to complex nanostructures with emergent functionalities.
• Chiroptical properties, particularly circular dichroism (CD), are important for sensing and optical applications.

Purpose of the Study:

• To develop a peptide-based method for creating double-helical gold nanoparticle superstructures.
• To investigate the relationship between structural parameters and chirooptical properties.
• To demonstrate the tunability of chirooptical activity through controlled overgrowth.

Main Methods:

• Peptide-directed self-assembly of gold nanoparticles into double-helical structures.
• Characterization of superstructures using electron microscopy and optical spectroscopy.
• Theoretical modeling to correlate structure with chirooptical response.
• Controlled silver overgrowth on gold nanoparticle superstructures.

Main Results:

• Successfully synthesized diverse double-helical gold nanoparticle superstructures with controllable handedness and dimensions.
• Observed well-defined circular dichroism (CD) signatures in the visible spectrum, linked to collective nanoparticle interactions.
• Demonstrated predictable and tailorable chirooptical properties by adjusting helical metrics and structure.
• Showed that silver overgrowth precisely modifies the intensity, position, and nature of chirooptical activity.

Conclusions:

• Peptide-based assembly is a versatile platform for designing complex plasmonic nanomaterials.
• Structural control over nanoparticle superstructures allows for precise tuning of chirooptical properties.
• The developed methodology enables the creation of advanced plasmonic materials with tailored optical responses for various applications.