Abstract
Interferometric scattering microscopy (iSCAT) is emerging as a powerful label-free optical method to directly visualize nanoscale dynamics in real time. While it catalyzed major progress in single-molecule studies in life sciences, its broader potential in chemistry and materials science is only beginning to unfold. This Perspective introduces iSCAT to the energy-materials community, highlighting how its sensitivity to subtle refractive-index changes enables direct observation of dynamic phenomena central to device performance and materials function. Ranging from single-particle energy conversion, and phase transformations to exciton and heat transport in semiconductors, from nanoparticle nucleation and growth up to self-assembly and framework formation, iSCAT provides spatiotemporal insights inaccessible to conventional techniques. We outline configurations most relevant to energy research to help researchers assess compatibility with their systems. By rendering the dynamics of transformation visible, iSCAT reshapes how materials processes are probed under realistic conditions.