Harvesting the sun

 

Commercial solar panels usually transform less that 20 percent of the usable energy that strikes them into electricity. The team estimate that individual nanoantennas can absorb close to 80 percent of the available energy. The circuits themselves can be made of a number of different conducting metals, and the nanoantennas can be printed on thin, flexible materials like polyethylene, a plastic that's commonly used in bags and plastic wrap.

 

By focusing on readily available materials and rapid manufacturing from inception, Novack says, the aim is to make nanoantenna arrays as cheap as inexpensive carpet.

 

Double-sided panels could absorb energy from the sun during the day, while the other side might take in the narrow frequency of energy produced from the earth's radiated heat. It may be possible to charge portable battery packs, coat the roofs of homes and even be integrated into polyester fabric.

 

While the nanoantennas are easily manufactured the researchers still need to develop a process to create a way to store or transmit the electricity. Although infrared rays create an alternating current in the nanoantenna, the frequency of the current switches back and forth ten thousand billion times a second. That's much too fast for electrical appliances, which operate on currents that oscillate only 60 times a second. So the team is exploring ways to slow that cycling down, possibly by embedding energy conversion devices like tiny capacitors directly into the antenna structure as part of the nanoantenna imprinting process.

 

The next generation of solar energy collectors may only be a few years away say the scientists.

 

For more attend Printed Electronics Europe 2008. Also read Organic and Printed Electronics in North America.