When President Obama recently called for a “Sputnik moment” to inspire a new generation of American innovation, he probably did not expect researchers at Stanford University to answer with a waffle iron. However, that pretty much summed up what happened, at least in the nanoscale world of plasmonics. It could lead to a new generation of affordable, high efficiency solar panels that will be as ubiquitous as, well, waffle irons.
“Waffle Iron” Solar Technology
As described by Stanford writer Andrew Myers, the researchers used a batter made mostly of titania, a semi-porous, transparent metal that is becoming useful in new solar technologies. First, they spread the titania batter on a base. Then they used a nano-scale waffle iron to imprint the batter with a honeycomb pattern. To bash the waffle metaphor even more, they filled the dimples with a layer of butter in the form of light-sensitive dye. They finished off with a layer of silver “syrup,” which hardened over the filled-in dimples to form domes.
High-Efficiency Thin Film Solar Cells
The result of all this is a concoction that Iron Chef could only dream of. The silvery bumps make unabsorbed light ricochet around until they get absorbed, which makes the new film more efficient. In addition, the use of light absorbing dye makes the new film less costly than conventional silicon solar cells (though in terms of relative efficiency and durability, dyes have have some catching up to do).
Plasmonics and Solar Cells
Myers notes that the Stanford film also contains a “secret ingredient:” the plasmonic effect. Plasmonics is an emerging field that exploits the ability of light and metal to create energy. Under the under the right conditions, light interacts with metal to produce electrical pulses, similar to sound waves. This property enabled the researchers to create a film that is far thinner than conventional thin film solar technology. With improvements in efficiency and durability, the new film could be applied to a wide range of uses, including many small, portable products as well as larger stationary solar arrays.
Image: Waffles by chadmiller on flickr.com.
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