  Energetic and optical properties of plasmonic nanocrystals strongly depend on
their sizes, shapes, and composition. Whereas using plasmonic nanoparticles in
biotesting has become routine, applications of plasmonics in energy are still
early in development. Here, we investigate hot electron (HE) generation and
related electromagnetic effects in both mono- and bi-metallic nanorods (NRs)
and focus on one promising type of bi-metallic nanocrystals - core-shell Au-Ag
nanorods. The spectra of the NRs are broadband, highly tunable with their
geometry, and have few plasmon resonances. In this work, we provide a new
quantum formalism describing the HE generation in bi-metallic nanostructures.
Interestingly, we observe that the HE generation rate at the UV plasmon
resonance of Au-Ag NRs appears to be very high. These HEs are highly energetic
and suitable for carbon-fuel reactions. Simultaneously, the HE generation at
the longitudinal plasmon (L-plasmon) peaks, which can be tuned from the yellow
to near-IR, depends on the near-field and electromagnetic Mie effects, limiting
the HE efficiencies for the long and large NRs. These properties of the
L-plasmon relate to all kinds of NRs (Au, Ag, and Au-Ag). We also consider the
generation of the interband d-holes in Au and Ag, since the involvement of the
d-band is crucial for the energetic properties of UV plasmons. The proposed
formalism is an important development for the description of bi-metallic (or
tri-metallic, or more complex) nanostructures, and it paves the way to the
efficient application of the plasmonic HEs and hot holes in sensing,
nanotechnology, photocatalysis, and electrophotochemistry.
