Electron transport and redox reactions in molecular electronic junctions.

Electron transport through single molecules or collections of molecules oriented in parallel can occur by several mechanisms, including coherent tunneling, activated transfer between potential wells, various "hopping" modes, etc. Given suitable energy levels and sufficiently long charge transport times, reduction or oxidation with accompanying nuclear reorganization can occur to generate "polarons", that is, localized redox centers in the molecule or monolayer. Redox events in molecular junctions are amenable to spectroscopic monitoring in working devices, and can have major effects on the electronic behavior of the junction. Several examples are presented, along with a possible application to molecular memory.