Electrodes affect electron hopping

Fig. 5 A model for current rectification in a molecular junction Shown are the chemical potentials fii and /ur in the two electrodes, and the HOMO and LUMO levels of the donor, acceptor, and bridge. When the right electrode is positively biased, (as shown) electrons can hop from left to right as indicated by the dotted arrows. If the opposite bias can be set without affecting the electronic structure of the DBA system too much, the reverse current will be blocked.

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