Theory of hot-carrier generation and relaxation in plasmonic nanoparticles*

Hot-carrier generation from surface plasmon decay has attracted much recent attention due to its promising applications in physical, chemical, materials and energy science. However, the detailed mechanisms of plasmonic hot-carrier generation and relaxation are less studied or treated by the semiclassical model. In this work, we develop and apply a quantum-mechanical model and coupled master equation method to study the generation, relaxation, and extraction of hot-carriers. And the connection with the semiclassical model is discussed. The initial distribution of hot-carriers and lifetimes of hot-carriers induced by different excitation are investigated. The relaxation due to electron-electron and electron-phonon scatterings are treated on the equal footing. Heat generation from hot-carriers decay is also described. We also generalize the model to study the extraction of hot-carriers to attached molecules or semiconductors. The quantum yield of extracting hot-carriers from the plasmonic nanoparticles is found to be size-dependent.