Half-wave organic-rectifiers with donor/acceptor assemblies in the molecular scale

We fabricate molecular rectifiers based on a monolayer of a donor molecule and a monolayer of an acceptor molecule in sequence. We characterize the donor/acceptor assemblies under ac voltage. We show that high-frequency half-wave rectifiers can be fabricated and characterized from the molecular assembly. From the frequency-response of the half-wave rectifiers, we study time responses of the processes that are responsible for the observed molecular rectification. We comment on the three steps of a molecular rectifier – the steps being electron-transfer to the acceptor moiety, electron-withdrawal from the donor moiety, and charge-transfer between an anionic-acceptor and a cationic-donor. The results show that the latter process is a slow one that may be due to conformational-change of the anionic-acceptors upon oxidation.