Hot-electron dynamics in plasmonic nanostructures: fundamentals, applications and overlooked aspects

Light absorption near a surface of conductive materials and nanostructures leads to the excitation of nonequilibrium, high-energy charge carriers: electrons above the Fermi level or holes below it. When remaining inside a material, these so-called hot carriers result in nonlinear, Kerr-type, optical effects important for controlling light with light. They can also transfer into the surroundings of the nanostructures, resulting in photocurrent, or they can interact with adjacent molecules and media, inducing photochemical transformations. Understanding the dynamics of hot carriers and related effects in plasmonic nanostructures is important for the development of ultrafast detectors and nonlinear optical components, broadband photocatalysis, enhanced nanoscale optoelectronic devices, nanoscale and ultrafast temperature control, and other technologies of tomorrow. In this review, we will discuss the fundamentals of plasmonically-engendered hot electrons, focusing on the overlooked aspects, theoretical descriptions and experimental methods to study them, and describe prototypical processes and examples of most promising applications of hot-electron processes at the metal interfaces.