In "The Matrix," computer-based life forms had enslaved humans on Earth and used their bodies as a power source. The humans served as the computers' limited-life batteries (batteries which can be recharged, but not indefinitely), similar to the way we'd use AA batteries in a TV remote control. Though "The Matrix" is fiction, researchers developing nanogenerators are finding reality in harnessing the body's energy to power electronic devices.
Dr. Zhong Lin (Z.L.) Wang of the Georgia Institute of Technology (Georgia Tech) is a leading researcher in nanogeneration [source: Nano]. For more than a decade, Wang and his team have been working to produce incredibly small circuits which can generate electrical current. Nanotechnology projects like the ones developed by the Georgia Tech team are so tiny that researchers must use microscopes to see what they're working on and instruments that can create and manipulate microscopic electronic components and measure their output [source: Illinois, Ravindran].
Dr Wang's team develops their nanogenerators entirely within their lab. Wang and his colleagues start by creating the materials they need and then fabricates, analyzes, measures and packages each nanogenerator prototype. This ground-breaking research group has successfully powered a light-emitting diode [LED], alaser diode and a liquid crystal display [LCD] using nanogenerated power exclusively [source: GeorgiaTech].
Different groups have experimented with different piezoelectric materials during their nanogenerator exploration. Researchers Michael McAlpine at Princeton University and Prashant Purohit at the University of Pennsylvania have been using lead zirconate titanate, or PZT. Though PZT is extremely brittle, McApline and Purohit discovered how to shape the material so it could stretch up to ten percent without breaking [source: Berger]. In 1999, Wang became the first researcher using zinc oxide (ZnO) as the piezoelectric material used in the nanogenerators [source: GeorgiaTech]. In a 2009 publication, Wang's team credits the use of ZnO for their continued success in improving nanogenerators [source: Lu, et al.].
We know piezoelectric material is the key component of a nanogenerator. Now, let's take a closer look inside to see just how it generates electricity.