CaSTL Seminar by Martin Moskovits

That the conduction electrons inhabiting nanostructured metals and other conductors can sustain resonances involving the coherent, collective dynamics of the electrons – plasmon resonances – has been known and understood for the better part of a century. These resonances can store great quantities of energy, which on dephasing can result in numerous energetic electrons (and holes) which thermalize by electron-phonon interactions over a few picoseconds. Hot electron phenomena such as enhanced photoemission from plasmonic systems have been known for many years. A great deal of research has recently been undertaken by dozens (perhaps hundreds) of groups world-wide with the aim of utilizing these hot electrons and holes to carry out photochemistry, often inspired by photosynthesis, and, to a lesser extent, as alternative strategies for producing photovoltaics.  The efficiency of such processes are now understood to involve multiple properties and steps, each of which can be rate limiting. The potential now exists for choosing plasmonic nanostructures that perform double duty: as light absorbers and sources of charge carrier, as well as appropriate surfaces that provide the surface-chemical and/or catalytic opportunities where desirable redox chemistry can take place. Some examples of such plasmonically-mediated photo-processes will be discussed.