Interfacial Role of Dopant d-States on Hot Carrier Generation in Bimetallic Nanoparticles

Metallic nanoparticles are of great interest due to a collective localized surface plasmon resonance (LSPR), which decays through Landau damping and results in a nonthermal distribution of electrons and holes, so-called hot carriers, the generation and harnessing of which are significant for photocatalysis, photovoltaics, and sensing. Bimetallic nanoparticles give the opportunity to tune their electronic structure to selectively produce hot carriers with desired energies. Using time-dependent density functional theory, we study magnesium nanoparticles doped with Ag, Au, Cu, and Pd to investigate how the different electronic structure of dopant atoms impacts the LSPR and plasmonic hot carrier generation. Although the photoabsorption of the nanoparticle is only slightly affected by dopant atoms, the hot carrier energy distribution significantly depends on the dopant types and their spatial distribution. Specifically, interface dopants enhance hot carrier generation more than those located deeper within the dopant domain, highlighting the role of spatial arrangement in heterostructured nanoparticles. These findings demonstrate that bimetallic nanoparticles exhibit promising performance depending on the constituent elements and their spatial distribution, which opens up the possibility of tuning the generation of hot carriers with appropriate-sized dopant clusters and interfaces through the generation and decay of LSPRs.