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Plasmon coupling in clusters composed of two-dimensionally ordered gold nanocubes
Huanjun Chen1, Zhenhua Sun, Weihai Ni
1Department of Physics, The Chinese University of Hong Kong Satin, Hong Kong SAR, P.R. China.
Small (Weinheim an Der Bergstrasse, Germany)
|June 23, 2009
Summary
Gold nanocube clusters show size-dependent plasmon coupling. Larger, asymmetric clusters and thermal treatment alter scattering peaks, impacting optical properties for nanomaterials applications.
Area of Science:
- Plasmonics
- Nanomaterials Science
- Optical Spectroscopy
Background:
- Understanding plasmon coupling in nanoparticle clusters is crucial for designing advanced optical materials.
- Gold nanocubes offer unique plasmonic properties due to their shape and symmetry.
Purpose of the Study:
- To investigate the influence of cluster size, ordering, and thermal treatment on the plasmon coupling of gold nanocubes.
- To correlate structural variations with observed optical scattering properties.
Main Methods:
- Assembly of gold nanocubes into clusters on indium tin oxide substrates.
- Characterization using dark-field imaging and finite-difference time-domain (FDTD) calculations.
- Analysis of optical scattering spectra before and after thermal treatment.
Main Results:
- Larger and more asymmetric clusters exhibited increased scattering peaks at longer wavelengths.
- Vertical dipole coupling with the substrate produced a fixed and a red-shifting scattering peak.
- Horizontal dipole coupling generated multiple low-energy peaks sensitive to cluster configuration; thermal treatment sharpened peaks and red-shifted lower-energy oscillations.
Conclusions:
- Plasmon coupling in gold nanocube clusters is highly tunable by cluster architecture and post-assembly processing.
- The findings provide insights into controlling light-matter interactions at the nanoscale for plasmonic devices.
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