Plasmonic Coupling in Linear Chains and Rings of Silver Nanoparticles Prepared by AFM Manipulation

We report the atomic force microscopy assembly of linear nanoparticle chains composed of two-to eight-particle linear and circular assemblies. Assembling particles into chains alters their plasmon resonance, forming transverse and longitudinal modes that can be excited and imaged using a polarizer and dark-field microscopy. The spectra generally agree with discrete dipole simulations, and the simulations show the importance of the dark field incident light angle. The work provides a straightforward method to assemble nanostructures with pristine nanoparticles and study their plasmonic properties.