While it's unlikely that nanogenerators will ever generate enough power to support large electronic devices like computers or TVs, a plethora of small devices could eventually be solely or partially powered by HONG chips. By 2013, Wang sees self-powered phones, digital music players and even a wireless keyboard powered by nothing more than the musician's keystrokes.
Wang says that the cost of adding a nanogenerator to devices would be low, because zinc oxide is a common material and HONGs are made with current semiconductor processing technology -- although some evolution of processing techniques will be needed. Additionally, HONG chips could lower the cost of certain products by partially or totally doing away with the need for a battery -- one of the most expensive components of any phone or music player.
Members of Wang's research group are also experimenting with more exotic, and potentially higher-power, piezoelectric compounds such as lead zirconate titanate, but they might be harder to process.
The bottom line is that for many of the electronic devices that surround us, the tyranny of the AC outlet and charger may end. "Motion is everywhere, waiting to be used for powering our future," says Wang. "All we need to do is harness it."
Wireless power: Electricity in the air
More than a century ago, electrical genius Nikola Tesla performed pioneering research and development on many of the things we take for granted today, from X-rays and alternating current electricity to efficient motors and generators and the precursors of radio. But when he turned his vivid imagination to sending electricity over the air with radio waves to power all sorts of devices and appliances without cords, it was an expensive failure.
Fast-forward to the present, where a company called Powercast is doing just what Tesla dreamed of: transmitting power via radio waves. "In a real sense, we're picking up where Tesla left off," says Harry Ostaffe, vice president for marketing and development at the Pittsburgh-based vendor. "We are sending power over the air for devices where it is expensive or inconvenient to change batteries."
Called power harvesting, the technique uses the company's book-size Powercaster transmitter to send either 1 or 3 watts of electricity into the air at the 915MHz radio frequency. At the receiving end, the power is pulled from the air by one of the company's Powerharvester chips, which convert RF energy to DC power.