Scientists from the Georgia Institute of Technology have created the world's first 3-D photovoltaic solar system that actually works underground.
Using optical fibers common to the telecommunications industry, researchers seeded them with zinc oxide nanostructures--much like the white stuff found on a lifeguard nose. Those nanostructures were then coated with a dye-sensitized material that converts light into electricity. The electricity is then captured using a liquid electrolyte surrounding the nanostructures.
So only the very tip of the cable needs to be exposed to actual sunlight.
This 3-D system can be easily concealed, leaving rooftops panel-free. It gives architects and designers new options for incorporating PVs into buildings. For each cable is only 3-times the width of a human hair.
"This will really provide some new options for photovoltaic systems," Dr Zhong Wang of the Georgia Institute of Technology said. "We could eliminate the aesthetic issues of PV arrays on building."
Once the light reaches the end of the fiber, it bounces back, actually doubling the chances for absorption. The result is up to six times more efficient than planar zinc oxide cells with the same surface area.
The fibers can be cut to any length: a 10-centimeter fiber results in about 0.5 volts.
Though the scientists have only reached an efficiency of 3.3 percent but hope to soon reach 8 percent. One improvement is collecting the charge with a titanium oxide surface coating. Of course, that's a bit short from the average 12 percent that much more expensive silicon-based solar panels get.
"No one wants to buy a big, nice, fancy car with a huge solar panel on the roof," says Wang.
Dye-sensitized solar cells use a photochemical system for generating electricity. While they are cheap to manufacture, flexible and mechanically robust, they have a lower conversion efficiency than that of silicon-based cells. Producing highly-efficient panels requires temperatures of several hundred degrees whereas these optical fibers require the same temperature as your morning Starbucks.
"This is a different way to gather power from the sun," Wang said. "To meet our energy needs, we need all the approaches we can get."
I couldn't agree more.