Studying the electrochemistry of single nanoparticles with surface plasmon resonance microscopy

Surface plasmon resonance microscopy (SPRM) is an emerging label-free optical microscopic imaging technology. It utilizes the planar surface plasmon resonance effect to visualize the optical mass of individual nano-objects. On the basis of appropriate optical-to-electrochemical conversion models, electrochemical current associated with individual nanoparticles can be quantitatively resolved from SPRM images recorded during electrochemical reactions, allowing for cyclic voltammetry and chronoamperometry analysis at single nanoparticle level. More importantly, the spatial resolution of SPRM further enables us to investigate the structure-activity relationship in a bottom-up manner by correlating the structure (from electron microscopes) and the electrochemical activity (from SPRM) of the very same individuals. In this mini-review, we summarize our recent work on using SPRM to study the electrochemical activities of single nanoparticles, and provide our opinions on the challenges and future research directions in this field.