Colorful Glass Delivers Massive Solar Energy Boost
Colored dyes mixed into glass could provide a major boost to a solar cell's ability to squeeze as much energy as possible out of a beam of sunlight. The technique, discovered by scientists at MIT, shepherds light to the edge of the glass, where it can be collected and converted into energy.
07/11/08 11:11 AM PT
The secret to affordable fuel-free energy may lie in some pretty-looking glass. Scientists at the Massachusetts Institute of Technology have found a way to use dye-colored glass to harness clean and renewable energy -- and to do it in a practical and cost-effective way.
The research, published in Friday's Science journal, builds off ideas first tested in the '70s. The work back then, however, never found a way to effectively absorb the light without losing its energy.
Hanging Onto Light
The MIT procedure uses something called a "solar concentrator." Unlike the 1970s-era devices, this creation is able to grab the light -- and then hang onto it. The concentrator can send the light at a much longer distance than past models have achieved, shooting the energy straight into solar cells along the glass's edge.
"Once the light is trapped inside, a major loss mechanism is that it can be reabsorbed by another dye molecule on its way out," MIT researcher Jon Mapel -- one of the study's authors -- told TechNewsWorld. "Every time that happens, there's a chance that it can get lost. It ends up going through a loss-absorption-reemission cycle, and eventually you lose too many of them and not enough get to the edges," he explained.
It's a problem that's plagued the field of solar research for decades -- and until now, there hasn't been a strong solution.
"A lot of technology goes into ensuring that the light is transmitted to the edge of the glass panel," Rob Collins, professor of physics at the University of Toledo, told TechNewsWorld. "Oftentimes, when you illuminate a dye, it will radiate in all directions. What you want to do is capture it within a glass, [and] they have established a way of efficiently doing this."
The solar concentrator results in 10 times more energy being created than what current systems can provide -- and theoretically, it can do it at a fraction of the price.
"Since you're using a lot less solar cells, you can potentially reduce the cost of solar electricity," Mapel said.
The system may also have appeal to homeowners wary of putting huge panels on their roofs. The solar concentrator could actually become part of your house -- without any unattractive addition.
"You could do dual-use as a window or skylight, where you have some light passing through but also have power being produced by it. It could be interesting because it would have those aesthetic advantages," Mapel pointed out.
For people willing to go the full mile, though, the concentrator could double up with a regular solar panel to boost energy efficiency by a pretty big margin.
"A solar panel's pretty good at absorbing infrared light, but it doesn't do as good of a job at trapping as much power out of the visible spectrum as it could. You put this concentrator on top, you'd get more power of the visible ... and end up with a combined system that could be up to 50 percent higher in power conversion efficiency," Mapel said.
The MIT team estimates the products could become widely available within the next three years.
The research was funded by the U.S. Department of Energy's Office of Science and the National Science Foundation. The organizations know any scientific study is always a risk -- but successes like this one make the investments worth their while.
"When the project began, there [was] no way to know that this would have been one of the end results," Josh Chamot, a spokesperson for the National Science Foundation, told TechNewsWorld. "It's very rewarding for us to see these types of research results come out of those sorts of collaborations."
The findings are equally rewarding for the science community -- much of which has waited years for this kind of development.
"It's quite exciting for us scientists working in that area," Collins said. "We'll obviously look at this quite seriously."