Reversible Switching in Molecular Electronic Devices

Here we compare the change in conductance when molecules wired between the ends of individual single-walled carbon nanotubes are switched between different states of conjugation. Our experimental approach utilizes electrodes made by excising a nanoscale section from an individual single-walled carbon nanotube. We use amide bond formation to incorporate photoswitches, diarylethenes, into these electrodes. The thiophene-based molecular bridge when incorporated into these SWNT can be switched from the open form to the closed form but not back again. If we use the pyrrole-based photoswitch, we can cycle between the open and closed states.