  Metal nanoparticles are excellent light absorbers. The absorption processes
create highly excited electron-hole pairs and recently there has been interest
in harnessing these hot charge carriers for photocatalysis and solar energy
conversion applications. The goal of this Perspectives article is to describe
the dynamics and energy distribution of the charge carriers produced by photon
absorption, and the implications for the photocatalysis mechanism. We will also
discuss how spectroscopy can be used to provide insight into the coupling
between plasmons and molecular resonances. In particular, the analysis shows
that the choice of material and shape of the nanocrystal can play a crucial
role in hot electron generation and coupling between plasmons and molecular
transitions. The detection and even calculation of many-body hot-electron
processes in the plasmonic systems with continuous spectra of electrons and
short lifetimes are challenging, but at the same time very interesting from the
point of view of both potential applications and fundamental physics. We
propose that developing an understanding of these processes will provide a
pathway for improving the efficiency of plasmon-induced photocatalysis.

Mesoscale and Nanoscale Physics