Supercharging Superlocalization Microscopy: How Electrochemical Charging of Plasmonic Nanostructures Uncovers Hidden Heterogeneity.

Superlocalization microscopy enables the position of single plasmonic nanoparticles to be determined with <25 nm precision, enabling single-nanoparticle tracking and super-resolution imaging experiments to be conducted with sub-diffraction-limited spatial resolution. In many of these applications, the superlocalized position of the nanoparticle is assumed to correspond to the geometric center of the nanoparticle. However, work reported by Wang and co-workers in this issue of ACS Nano suggests that this assumption can be incorrect, based on studies in which electrochemically charging a nanoparticle leads to reproducible shifts in its scattering center. The shift is believed to originate from nonuniform charge accumulation in the nanoparticle, due to the inherent heterogeneity in nanoparticle surface properties. This Perspective explores the implications of this result, both for using this shift to probe dynamic changes in nanoparticle surface chemistry as well as for exploiting nonuniform charge accumulation to promote site-specific chemical reactions.