Rational Growth of Symmetric Nanoparticle Arrays into Asymmetric Ones for Surface-Enhanced Raman Scattering Sensing...

Area of Science:

• Nanotechnology
• Materials Science
• Plasmonics

Background:

• Asymmetric plasmonic nanoparticles offer unique properties for sensing applications.
• Fabricating ordered asymmetric nanoparticle arrays is challenging due to growth and assembly limitations.

Purpose of the Study:

• To develop a reliable method for fabricating asymmetric plasmonic nanoparticle arrays.
• To investigate the surface-enhanced Raman scattering (SERS) properties of these arrays for sensing.

Main Methods:

• Assembly of symmetric nanoparticles into ordered arrays.
• Directed growth into asymmetric arrays using a ligand patch-protected selective growth strategy.
• Fabrication of gold nanomushroom (NM) and nanosingle-pyramid (NSP) arrays.

Main Results:

• Precise control over lateral or vertical growth of ligand patchy-protected Au nanorice arrays.
• Achieved significantly higher SERS activity in Au NM arrays compared to Au NSP arrays (approx. 126 times).
• Finite-difference time-domain simulations confirmed electromagnetic field amplification in Au NM arrays.

Conclusions:

• The developed ligand-protected selective growth strategy enables precise fabrication of asymmetric nanoparticle arrays.
• Au NM arrays exhibit exceptional SERS enhancement factors (up to 10^9) at small interparticle gaps (~3 nm).
• These asymmetric arrays show great potential for advanced sensing and spectroscopy applications.