Molecular switch tunnel junction

Delonno E, Tseng HR, Harvey DD, Stoddard JF, Heat JR (2006) Infrared spectroscopic characterization of [2]rotaxane molecular switch tunnel junction devices. J Phys Chem B 110 7609-7612... 

A Redox-driven [2]Rotaxane-based Molecular Switch Tunnel Junctions (MSTJs) Device... 

Stoddart and co-workers have developed molecular switch tunnel junctions [172] based on a [2]rotaxane, sandwiched between silicon and metallic electrodes. The rotaxane bears a cyclophane that shuttles along the molecular string toward the electrode and back again driven by an electrochemical translation. They used electrochemical measurements at various temperatures [173] to quantify the switching process of molecules not only in solution, but also in self-assembled monolayers and in a polymer electrolyte gel. Independent of the environment (solution, self-assembled monolayer or solid-state polymer gel), but also of the molecular structure - rotaxane or catenane - a single and generic switching mechanism is observed for all bistable molecules [173]. 

The results of these condensed-phase switching experiments provide us with the impetus to incorporate the bistable [2]catenane 4" into solid-state electronic devices. In collaboration with members of the Heath group in the California NanoSystems Institute (CNSI) here at UCLA, the [2]catenane 4 4DMPA was introducedfirst of all into two-terminal devices to form molecular switch tunnel junctions (MSTJs) in which each MSTJ functions as an electronically reconfig-... 

Another active, connected device, a molecular switch tunnel junction, has been prepared based on the switching of a two-station rotaxane. At a specific voltage, the system switches from a stable state (isomer) to a metastable one with a different conductivity. It then remains in that state until another voltage pulse returns it to its initial form (isomer). 

Fig. 6 An intrinsic molecular switch positioned in an STM tunnel junction. Here, the mechanism of intramolecular switching is independent of the surface. It is the intramolecular transfer of two protons which is supposed to shift the molecular orbitals of molecule since one phenyl is bonded to a sulfur atom. The protons transfer is triggered by the tip to surface electric field...

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