Watching operando nanoscale electrochemical deposition by optical microscopy

Electrodeposition is a popular electrochemical technique which has recently shifted from the deposition of conformal thin films to the deposition of nanoparticles and the fabrication of nanostructured electrodes. It is straightforward to implement for catalysis and sensing applications and it allows producing surfactant-free and perfectly connected nanoparticles whose size, shape, and composition can be modulated by the applied potential or current. Meanwhile, the underlying mechanisms of nanoparticle nucleation and growth are still under intensive investigation thanks to the considerable technological improvements made in many high resolution (operando or identical location) imaging techniques over the last two decades. This review focuses on the recent advances made by optical microscopy in this field. It is indeed now possible to use high resolution optical microscopes to probe objects noninvasively and operando at the nanoscale with a very high temporal resolution and high throughput, which is of particular interest for electrodeposition studies.