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First practical nanogenerator produces electricity with pinch of the fingers

After six years of intensive effort, scientists are reporting development of the first commercially viable nanogenerator. It’s a flexible chip that can use body movements – a finger pinch or a pulse beat – to generate electricity.

“This development represents a milestone toward producing portable electronics that can be powered by body movements without the use of batteries or electrical outlets,” said lead scientist Zhong Lin Wang, Ph.D. “Our nanogenerators are poised to change lives in the future. Their potential is only limited by one’s imagination.”

The latest improvements have resulted in a nanogenerator powerful enough to drive commercial liquid-crystal displays, light-emitting diodes and laser diodes. By storing the generated charges using a capacitor, the output power is capable of periodically driving a sensor and transmitting a signal wirelessly.

“If we can sustain the rate of improvement, the nanogenerator may find a broad range of other applications that require more power,” he added. Wang cited, for example, personal electronic devices powered by footsteps activating nanogenerators inside the sole of a shoe; implanted insulin pumps powered by a heart beat; and environmental sensors powered by nanogenerators flapping in the breeze.

Wang and colleagues demonstrated commercial feasibility of the latest nanogenerator by using it to power an LED light and a liquid crystal display like those widely used in many electronic devices, such as calculators and computers. The power came from squeezing the nanogenerator between two fingers.

The key to the technology is zinc oxide (ZnO) nanowires. ZnO nanowires are piezoelectric – they can generate an electric current when strained or flexed. That movement can be virtually any body movement, such as walking, a heartbeat, or blood flowing through the body. The nanowires can also generate electricity in response to wind, rolling tires, or many other kinds of movement. The diameter of a ZnO nanowire is so small that 500 of the wires can fit inside the width of a single human hair.