Physicists successfully control nanomachines with ultraviolet light

Washington, July 3 : Physicists at the University of California at Berkeley have been able to use light to control and move nanomachines.

During experiments they found that by shining ultraviolet light on tiny molecules of azobenzene adhered on a layer of gold, they could force the molecules to change shape at will.

Previous experiments with shape-shifting azobenzene had shown that the molecules only responded properly when suspended in liquids or incorporated into plastics, neither of which made a very good foundation for complex nanomachines.

This time round, the team added legs built of carbon and hydrogen atoms to hold the molecules slightly away from the metal.

Although the legs anchoring the molecules to the surface only provided a fraction of a nanometer of clearance (less than a billionth of a meter), it was enough to allow the molecules to move in response to the UV illumination.

A series of scanning tunnelling microscope images also confirmed that they could switch the molecules' shapes from one configuration and back again.

Researchers say the molecules could be incorporated into nanomachines in the form of remotely controlled switches, pistons or other movable components.

The findings appear in the journal Physical Review Letters.