Loo said the folding method promises to increase those numbers. Because the technique works with most types of plastic photovoltaic materials, it should provide a boost to efficiency across the board.
"This is a very simple process that you can use with any material," she said. "We have tested it with other polymers and it works as well."
Jong Bok Kim, a postdoctoral researcher in chemical and biological engineering and the paper's lead author, explained in the Nature Photonics paper that the folds on the surface of the panels channel light waves through the material in much the same way that canals guide water through farmland. By curving the light through the material, the researchers essentially trap the light inside the photovoltaic material for a longer time, which leads to greater absorption of light and generation of energy.
"I expected that it would increase the photocurrent because the folded surface is quite similar to the morphology of leaves, a natural system with high light harvesting efficiency," said Kim, a postdoctoral researcher in chemical and biological engineering. "However, when I actually constructed solar cells on top of the folded surface, its effect was better than my expectations."
Although the technique results in an overall increase in efficiency, the results were particularly significant at the red side of the light spectrum, which has the longest wavelengths of visible light. The efficiency of conventional solar panels drops off radically as light's wavelength increases, and almost no light is absorbed as the spectrum approaches the infrared. But the folding technique increased absorption at this end of the spectrum by roughly 600 percent, the researchers found.
"If you look at the solar spectrum, there is a lot of sunlight out th
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Princeton University, Engineering School