Probing Hot Electron Behaviors by Surface-Enhanced Raman Spectroscopy

Light-excited energetic electrons, or so-called hot electrons (HEs), in plasmonic metal nanostructures have received much attention in the past few years. Plasmonic metal nanostructures, acting as light absorbers with higher efficiency and adjustability than dye molecules and inorganic semiconductors, can generate HEs under specific light conditions. However, the overall efficiency of the plasmonic systems remain unsatisfactory. Therefore, it is important to study the gener ation and transfer processes of plasmon-induced HEs, which are necessary for efficient plasmon-enhanced applications. In this review, we summarize the basic concepts and mechanisms of HE generation and transportation, then highlight the use of in situ surface-enhanced Raman spectroscopy (SERS) as a probe for HE-induced chemical reactions. We also discuss the opportunities and remaining challenges in promoting fundamental understanding of, and practical applications for, HEs.