Electron-driven, switchable molecular nano-motor demonstrated

A team of researchers demonstrated a working example of a single-molecule motor, that can be switched to rotate in both directions, in a paper published in Nature Nanotechnology on Dec. 23, 2012. Researchers use the capabilities of scanning tunneling microscopes to manipulate single atoms and construct new molecules to build molecular nano-tech devices, among them molecular motors driven by light, chemical energy or in this case, electricity.

A single ruthenium atom acts as the axis or ball bearing, on which a rotor with iron atoms is able to rotate. The ruthenium atom sits on a small pyramid made of just one boron atom and a couple of other atoms, mostly nitrogen, around it forming the base of the motor.

To get the five-armed rotor spinning, Perera and his team used a scanning tunneling microscope to inject electrons to different parts of the rotor, thereby controlling the direction.

"The directional rotation arises from sawtooth-like rotational potentials, which are solely determined by the internal molecular structure and are independent of the surface adsorption site," explained the authors.