Description
Plasmonic nanoparticles have recently emerged as promising photocatalysts for light-driven chemical conversions. The illumination of these particles results in the generation of highly energetic charge carriers, elevated nanoparticle surface temperatures, and strongly enhanced electric fields around the nanoparticle. Distinguishing between these different physical mechanisms is of paramount importance for the design of future photocatalysts. However, characterizations of chemical reactions mediated by plasmonic effects are often performed at the ensemble level and are consequently plagued by the intrinsic heterogeneity of catalyst particles. Here, we report an in-situ single particle characterization of a chemical reaction driven solely by a plasmonic near-field. By using super-resolution fluorescence microscopy, we are able to achieve single turnover temporal resolution and ~30 nm spatial resolution. This sub-particle spatial resolution permits the construction of a clear correlation between the simulated electric field distribution around individual metal nanoparticles and their super-resolved catalytic activity maps. Our results can easily be extended to systems with more complex electric field distributions, such as dimers and plasmonic particle arrays, and can thereby guide the design of future advanced photocatalysts.
