Power from the wire

Researchers at the University of Illinois have shown that a single nanowire can produce power by harvesting mechanical energy.

Made of piezoelectric material, the nanowire generates a voltage when mechanically deformed. To measure the voltage produced by such a tiny wire, however, the researchers first had to build an extremely sensitive and precise mechanical testing stage.

Min-Feng Yu, a prof of mechanical science and engineering and graduate students Zhaoyu Wang, Jie Hu, Abhijit Suryavanshi and Kyungsuk Yum synthesized the nanowire in the form of a single crystal of barium titanate, an oxide of barium and titanium used as a piezoelectric material in microphones and transducers. The wire was approximately 280 nanometers in diameter and 15 microns long.

The precision tensile mechanical testing stage is a finger-size device consisting of two coplanar platforms - one movable and one stationary - separated by a three micron gap. The movable platform is driven by a single-axis piezoelectric flexure stage with a displacement resolution better than one nanometre.