Solar cells cross new threshold
By: Julie Freydlin, special to mongabay.comMarch 08, 2012
Many organic solar cells are single-layer—they contain a film-thin layer of the organic polymer between two transport layers. When photons strike the cell, they energize electrons, turning them into excitons. The energy in excitons can be converted to electricity. The reason why such cells are not efficient at the sun-to-electricity conversion is because the polymer only absorbs a part of the solar spectrum—a certain bandgap—not all of it. This means that much of the solar energy, which could be potentially turned into electricity, is lost.
 Jing-Bi You. |
“Devices with more than 10% efficiency,” says co-author Jing-Bi You, “could be incorporated into the products” that are commercially viable. For example, such cells can be used to provide electricity for cars, buildings, even planes.
“We also can make semi-transparent organic solar cell and put it on windows,” adds the paper’s co-author Letian Dou. “Then we will have colorful windows that can generate electricity during the daytime.”
However, such feats might be a while away. For now, scientists are only able to produce cells that have the maximum area of 1 cm2—definitely way too small to power a plane. But they are working hard to overcome this and other challenges so to that one day, we’ll just be able to charge our phones as we are strolling through a park on a nice day.
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