Semishells: versatile plasmonic nanoparticles.

Localized surface plasmon excitations in metal nanostructures have a strong impact on light scattering, absorption, and local field intensities at the nanoscale. Tweaking the nanoparticle shape, size, and material enables researchers to engineer the resonance wavelength position, the nanoparticles' local field enhancement, and their scattering properties. In particular, by breaking the symmetry of originally symmetric nanostructures, additional degrees of freedom can be explored. One particular example of a highly investigated nanostructure is the so-called semishell (or nanocup or nanocrescent moon). In this issue of ACS Nano, King et al. report on the angular and spectral scattering properties of plasmonic semishells and the effect of a high-index substrate on these properties.