Electron Transfer and Electronic Conduction through an Intervening Medium

摘要

Electron transfer(ET)and electronic conduction through single molecules,small groups of molecules,and biomol-ecules,or through an intervening medium(e.g.a host solvent or semiconductor)which contain electron donor(D)and/or acceptor(A)centers,are fundamental processes in chemistry,physics,and biology.Particularly interesting materials in this respect are doped semiconductors,and glasses containing transition-metal ions having two valences(e.g.Fe~(2+)and Fe~(3+)).Both of these two areas have been studied primarily by physicists analyzing the magnitude of the electrical conductivity of the system or material.Meanwhile,chemists and biochemists have examined single-site to single-site,donor-to-acceptor,electron transfer in liquid or frozen solutions of structured(rigid)molecular chains,in proteins,and in other biomolecules in experiments which have given electron-transfer rate constants.An area of activity which naturally couples the two situations is single-molecule transport junctions of molecular interconnects,which conduct electrical current between two nano-scale electrodes.