Molecular Electronics and Devices Home

Our group studies the electronic properties of molecular and mechanical systems at the  nanoscale. Most of the experiments we perform involve a combination of top-down nanotechnology and bottom-up nanotechnology.

Top-down nanotechnology is used to build nanometer-scale structures that are used as resonators or for instance to make electrical contact to single molecules or nanoparticles. The bottom-up technology we use include self-assembly techniques to contact the molecules between electrodes, place nanoparticles in well ordered arrays, but also to grow carbon nanotubes.

In the news:

An all-electric single molecular motor

Our group has recently proposed a conceptually new design for a molecular motor. The design is based on electric field actuation and electric current detection of the rotational motion of a molecular dipole embedded in a three-terminal single-molecule device. Although motors powered by light or heat are useful for driving large assemblies of molecules at once, it is very difficult to apply a force locally to drive a single molecular motor. With an electric field this becomes much easier. Moreover, the speed of rotation can be controlled very accurately by varying the frequency of the electric field. Although the direction of rotation of the proposed motor depends on its orientation in the junction, calculations show that it is uni-directional. One of the main challenges right now is to come up with a design that would provide full control over the direction of rotation.

Detection of the rotation of a molecular motor is a non-trivial issue, since the motion of a single molecule between electrodes is too small to image directly. However, our calculations show that for conjugated molecules it is possible to measure the rotation by looking at the variation in the conductance. Conjugated molecules prefer to be planar, and if they are, their conductance is high. But when the rotor starts to turn, the conductance drops. It is therefore possible in principle to measure the rotation angle of the rotor by looking at the conductance.

At the moment the motor exists only on paper. However, certain parts of the design have already been verified experimentally, and we are currently talking to chemists who have expressed an interest in synthesizing the proposed molecules. We also have openings for a PhD (experimental) and Postdoc (theoretical) position on this project.

This study was funded by Stichting FOM (project 86) and the EU FP7 program
under the grant agreement "SINGLE".