Hot carrier generation in a strongly coupled molecule–plasmonic nanoparticle system

Abstract

In strongly coupled light matter systems electronic energy levels become inextricably linked to local electromagnetic field modes. Hybridization of these states opens new relaxation pathways in the system, particularly important for plasmon decay into single electron states, known as hot carriers. We investigate the influence of the coupling strength between a plasmonic resonator and a molecule on hot carrier generation using first principles calculations. An atomistic approach allows the capture of changes in the electronic structure of the system. We show that hot carriers are not only preferably generated at excitation frequencies matching the new polaritonic resonances, but their energy distribution strongly deviates from the one corresponding to the non-interacting system. This indicates existence of new plasmon decay paths due to appearance of hybridized nanoparticle–molecule states. We observe also direct electron transfer between the plasmonic nanoparticle and the molecule. Therefore, we may conclude, that bringing plasmonic nanostructures in strong interaction with molecules gives the ability to manipulate the energy distribution of the generated hot carriers and opens possibility for charge transfer in the system.

Keywords

• hot carrier generation
• metallic nanoparticle
• molecule plasmon coupling
• strong coupling