Modelling hot-carrier generation in metallic nanoparticles containing more than one million atoms

Energetic or "hot" electrons and holes are generated in metallic nanoparticles from the decay of localized surface plasmons. These carriers can be used for applications in photocatalyis or sensing. A detailed understanding of the relationship between hot-carrier properties and the composition, shape, environment and size of metallic nanoparticles is needed to guide experimental efforts towards highly efficient hot-carrier devices. However, the modelling of experimentally relevant nanoparticles is challenging because of their large sizes often containing millions of atoms rendering standard electronic structure techniques, such as those based on first-principles density-functional theory, unfeasible. To overcome this challenge, I will introduce a new material-specific quantum-mechanical modelling approach that combines ab-initio derived tight-binding models with solutions of Maxwell's equations for the nanoparticle. To evaluate Fermi's golden rule for the localized surface plasmon decay for large nanoparticles, we employ a decomposition in terms of Chebychev polynomials combined with highly efficient stochastic trace evaluations. The resulting approach allows us to study hot-carrier generation in large nanoparticles of Au, Ag and Cu and understand the interplay of interband and intraband transitions as function of the nanoparticle size. In addition, results for hybrid nanparticles consisting of both plasmonic and catalytic metals will be discussed including core-shell architectures or satellite systems.