Today, solar cells are not a very efficient way to produce electricity, even if the source of energy is free. They can be manufactured from thick crystalline silicon wafers (300 microns thick) or thinner non-crystalline ones (about 2 microns thick). But 'thin' cells built are less efficient than 'thick' ones, even if they're cheaper to produce. But now, researchers at Iowa State University have found a way to boost the performance of these solar cells by 40 to 50 percent. And as they can be produced with the same manufacturing processes than previous ones, they'll remain cheap. Read more...
This research work has been led by Vikram Dalal, Director of the Microelectronics Research Center, and who studies solar technology for more than thirty years. For this specific project, he worked with PowerFilm Inc., a company that manufactures thin solar panels.
Here are some excerpts from the Iowa State University news release describing the problems they faced.
One of the challenges facing solar cell manufacturers is the fact that most cells are manufactured with crystalline silicon, the same material that's used to make computer semiconductors. Because computer parts have so much more value than solar cells, Dalal said there's a shortage of silicon for solar cells.
There is, however, a way to manufacture solar cells using a lot less silicon. Dalal said non-crystalline silicon wafers that are about 2 micrometers thick can replace crystalline wafers that are about 300 micrometers thick. The result is thin solar cells that can absorb lots of light and can be mounted on flexible plastic and other materials. It's the kind of solar cell technology produced by PowerFilm Inc. But the thin cells produce about half the electricity as crystalline silicon. And their performance drops by about another 15 to 20 percent over time.
Below you can see the technology used by PowerFilm Inc. to develop its products (Credit: PowerFilm Inc.). Here is a link to a larger version.
So what did these researchers find? Details are pretty scarce, especially when scientists say they might claim several patents for this technology.
Iowa State researchers have made discoveries in materials science and plasma chemistry that can improve hydrogen bonding to the silicon in the thin solar cells. And Dalal said that can improve the performance of the cells by about 35 percent and eliminate about 15 percent of the drop in performance.
I guess they don't want to give more details until their new technology is patented and protected. But they don't say when these solar cells become commercially available.
On another subject, Dalal looks back at 1972, when he his starts working on solar technology instead of developing bombs. "I find it is tremendously interesting, even after 34 years. And it helps humanity instead of killing it, which allows me to sleep at night."
Source: Iowa State University news release, September 18, 2006
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