New small-scale generator produces alternating current by stretching zinc oxide wires

Flexible charge pump

Image shows a prototype flexible charge pump that generates alternating current as zinc oxide wires are stretched and then released. Click here for more information.

Researchers have developed a new type of small-scale electric power generator able to produce alternating current through the cyclical stretching and releasing of zinc oxide wires encapsulated in a flexible plastic substrate with two ends bonded.

The new "flexible charge pump" generator is the fourth generation of devices designed to produce electrical current by using the piezoelectric properties of zinc oxide structures to harvest mechanical energy from the environment. Its development was scheduled to be reported November 9, 2008 in the advance online publication of the journal Nature Nanotechnology.

"The flexible charge pump offers yet another option for converting mechanical energy into electrical energy," said Zhong Lin Wang, Regent's professor and director of the Center for Nanostructure Characterization at the Georgia Institute of Technology. "This adds to our family of very small-scale generators able to power devices used in medical sensing, environmental monitoring, defense technology and personal electronics."

The new generator can produce an oscillating output voltage of up to 45 millivolts, converting nearly seven percent of the mechanical energy applied directly to the zinc oxide wires into electricity. The research has been supported by the U.S. Department of Energy, the National Science Foundation, the Air Force Office of Scientific Research and the Emory-Georgia Tech Center for Cancer Nanotechnology Excellence.