SOLAR SKIN: A SHEET OF TINY ANTENNAS

There is word of more progress from the materials scientists trying to make a next generation solar cell that will be cheap and easy to put to work.

While chemists are thinking about a paint with embedded nanoreceptors that catch the sunlight and transform it to electricity, materials scientists at the Idaho National Labs run by the U.S. Department of Energy have come up with a plastic with embedded nanoantennas that catch heat energy and transform it into electricity.

Capturing heat energy means capturing considerably more energy than capturing light. And it means capturing energy even when it is dark from any source of heat.

Because it captures heat, the plastic can be a “skin” for devices that drains away heat and turns it into electricity. It could power anything from an electric car to an Iphone.

Obstacle: The electricity generated from the heat is alternating current (AC) at a very high current, a current so high it requires a rectifier better than any now available. To use the skins, the INL research team must either invent a new kind of rectifier or develop new circuitry for the skin.

Eventually, INL hopes to develop double-sided skin to cover anything from building roofs to consumer gadgets, providing cheap, ongoing energy.

This video explains it.

Flexible Nanoantenna Arrays Capture Abundant Solar Energy
August 10, 2008 (DOE/Idaho National Lab via EurekAlert)

WHO
Idaho National Laboratories (INL) of the U.S. Department of Energy (DOE); Steven Novack, physicist/research team leader; INL; INL research team (Dale Kotter, engineer, INL; W. Dennis Slafer, MicroContinuum, Inc.; Patrick Pinhero, formerly INL & presently at the University of Missouri)

WHAT
Nanoantennas could be the key to a flexible, plastic, potentially inexpensive solar energy collector that would coat and power anything requiring electricity.

click to enlarge

WHEN
- Nanoantenna-embedded plastic sheets could someday power anything from an electric vehicle to an iPod.
- Findings reported August 13 at the American Society of Mechanical Engineers 2008 2nd International Conference on Energy Sustainability.
- While current solar cells generate electricity from light and only produce power during the day, the nanoantennas in the skins generate electricity from any available heat source and could produce power even at night.

WHERE
- Research from DOE’s Idaho National Labs.
- Findings reported at the conference in Jacksonville, Fla.
- Because the nanoantennas produce power from heat, locating them near a traditional power plant would allow them to generate electricity from the plant’s normally wasted thrown-off heat.

WHY
- The “skin” would also serve as an insulator by drawing off heat from the sun.
- The nanoantennas pick up mid-spectrum infrared light as heat energy whereas current solar cells pick up visible light.
- Nanoantennas: tiny gold squares or spirals set in a specially treated form of polyethylene (a plastic).
- Earliest tests were with silicon.
- With the right plastic materials, scientists expect to harvest 92% of available energy.
- The infrared current is very high, requiring a rectifier beyond the capacity of current technology.
- An alternative to new rectifier technology is new circuitry for the skin.
The production process lends itself to creating a double-sided skin and to mass production at several yards per minute.

click to enlarge

QUOTES
- Steven Novack, physicist/research team leader, INL: "Every process in our industrial world creates waste heat…It's energy that we just throw away."
- Dale Kotter, engineer/research team member, INL: "We need to design nanorectifiers that go with our nanoantennas…"