Harvesting Energy from Strange Sources
Cheap, yet efficient, solar cells could help wean us from dirty electricity sources. But that’s not what Zhong Lin Wang at Georgia Tech has in mind. Technology Review recognized his work on nanopiezotronics, nanowires and other structures that convert mechanical stress into electrical currents, in our special section on the 10 emerging technologies of the year. Zinc-oxide nanowires that produce an electrical current when stressed could provide a power source for implantable diagnostics and stress sensors embedded in buildings and bridges. These materials could also be woven into an iPod-charging jacket that harvests the small amount of energy produced by the rustling of fabric as you walk. A series of papers produced by Wang throughout the year further established the concept, showing that nanopiezotronics could harness the energy produced by a running hamster (“Harnessing Hamster Power with a Nanogenerator”), that they could act as stress sensors (“Nanosensing Transistors Controlled by Stress”), and that they could be combined with solar cells in a hybrid nanogenerator (“A Hybrid Nano-Energy Harvester”).
Optical Materials Advance
Part of the 2009 Nobel Prize in physics went to a researcher whose work formed the basis of modern telecommunications. Charles Kuo figured out why optical fibers that had been made in the lab in the 1960s weren’t working: the material contained impurities that attenuated the signal. Based on this finding, Kuo determined that pure glass could realize the potential of optical data transmission to speed the flow of information (“Nobel for Revolutionary Optical Technologies”). Modern optical fibers are even better than what Kao predicted, losing just 5 percent of the light over a distance of a kilometer; today there are over one billion kilometers of optical fiber around the world, with more being added each day.
And this year Intel announced its intention to replace copper wires used to carry data between your MP3 player, laptop, and other devices with optical fiber (“Intel’s Plan to Replace Copper Wires”). In 2010, the company will ship Light Peak data cables that will zip 10 gigabits of data per second between gadgets using light, which is much faster than electrons.
A fundamental advance in optics this year was the fabrication of an extremely small laser that may eventually be developed into a compact light source for optical computers (“The Smallest Laser Ever Made”). Optical devices can operate at hundreds of terahertz, compared to the 10 gigahertz speeds of the best consumer electronics. But optical devices are difficult to miniaturize. The “nano laser,” made by researchers at Cornell, Purdue, and Norfolk State universities, helps overcome this problem.
Ultradense Data Storage and Biodegradable Electronics
The year also brought innovative materials for storing more data for longer periods of time. Layers of gold nanorods that polarize light and reflect different colors can store data in five dimensions (“Five-Dimensional Data Storage”); optical antennas that focus light to tiny, intense spots to heat bits could extend the lifetime of magnetic data storage (“Heating Up Magnetic Memory”); and researchers at HP looked to magnetic nanowires to make racetrack memory (“TR10: Racetrack Memory”).
Meanwhile, researchers in Japan demonstrated the first plastic, flexible flash memory device, which might be incorporated into unconventional electronics such as disposable sensors (“Cheap, Plastic Memory for Flexible Devices”). Researchers in Illinois worked wonders with silicon to make electronics that took strange forms, including flexible LED arrays (“Cheaper LEDs”) and biocompatible electronics (“Implantable Silicon-Silk Electronics”) that could drive medical implants. These projects were led by John Rogers, who invented a stretchable silicon technology we recognized in 2006 (“Stretchable Silicon”). And at Stanford, researchers made the first fully biodegradable transistors, which might control drug delivery in future medical implants (“Biodegradable Transistors”).