Flexible nanoantenna could revolutionise production of cheap solar energy

Washington, August 11 : Researchers at the U.S. Department of Energy's Idaho National Laboratory claim to have developed an inexpensive technology that may one day help power everything from hybrid cars to iPods with higher efficiency than traditional solar cells.

They describe their breakthrough as a method to produce plastic sheets containing billions of nanoantennas that collect heat energy generated by the sun and other sources, the first step toward a solar energy collector that could be mass-produced on flexible materials.

The researchers say that the nanoantennas - tiny gold squares or spirals set in a specially treated form of polyethylene - also have the potential to act as cooling devices that draw waste heat from buildings or electronics without using electricity.

The traditional solar cells can only use visible light, rendering them idle after dark.

However, according to the researchers, the nanoantennas target mid-infrared rays, which the Earth continuously radiates as heat after absorbing energy from the sun during the day.

Infrared radiation is an especially rich energy source because it also is generated by industrial processes such as coal-fired plants.

"Every process in our industrial world creates waste heat. It's energy that we just throw away," says INL physicist Steven Novack.

The researchers say that the nanoantennas' ability to absorb infrared radiation also makes them promising cooling devices.

Since objects give off heat as infrared rays, the nanoantennas could collect those rays and re-emit the energy at harmless wavelengths, and the researchers are of the view that such a system could cool down buildings and computers without the external power source required by air-conditioners and fans.

The research group, however, concedes that more technological advances are needed before the nanoantennas can funnel their energy into usable electricity.

A presentation on this research will be made on August 13 at the American Society of Mechanical Engineers 2008 2nd International Conference on Energy Sustainability in Jacksonville, Florida.

ANI