Numerical Modeling\nof Transient Absorption in Hybrid\nDual-Plasmonic Au/CuS Nanocrystals

Colloidal hybrid\nAu/CuS nanocrystals have emerged as\nhighly interesting\ndual-plasmonic materials. Femtosecond transient absorption spectroscopy\n(TAS) revealed that the resonant excitation of the localized surface\nplasmon resonance of either Au or CuS results in a transient response\nin the counterpart, which we attributed to Landau damping stemming\nfrom hot carriers at the domain interface. Here, we employ numerical\nmodeling to further clarify the origin of the response in Au/CuS nanocrystals.\nNumerical simulations identify the UFO-shaped geometry of the Au/CuS\nnanocrystals, the anisotropy of CuS, and the plasmonic response modified\nby Landau damping during the TAS as the main governing mechanisms\nfor the dual-plasmonic optical response. Our numerical approach provides\nan important tool for the modeling of TAS data and provides valuable\ninsights for the design of innovative colloidal dual-plasmonic nanocrystals\nwith optical anisotropy for applications in photocatalysis, thermoplasmonics,\nand ultrafast photonics.