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Inside the polymer, electrons go from a low to a high energy level when bombarded by photons. The smaller the difference (or bandgap) between these levels, the more light a cell absorbs, and the higher its efficiency. One way to decrease the bandgap is to bring down the higher energy level. University of Chicago chemistry professor Yu is using this technique to design new types of narrow-bandgap polymers. "The beauty of organic solar cells is that we're able to engineer new materials that can tailor those energy levels," Yang says.
The researchers are also trying to improve the interface between the polymer and the carbon nanostructure so that electrons can move faster to the external circuit without getting trapped in the material. And they are developing better electrode materials and improved ways of fabricating the electrodes. Yang says these advances will eventually make it possible to boost the efficiency of individual cells and of stacked cells.
Even if Solarmer reaches its target of 10 percent efficiency, Wu says, it may take as long as three years before the company can print commercial-grade rooftop panels with those ratings. Right now, the company plans to have devices on laptop bags and cell phone back panels in early 2011, followed by awnings and sunshades.
Yang says organic solar cells need not only higher efficiencies but also more stability. "What's commercialized is not the highest efficiency but most reproducible technology," he says. Indeed, plastic solar startup Konarka, based in Lowell, MA, is producing flexible panels on a large scale despite just a 3 to 5 percent efficiency.
Adam Moulé, a chemical engineering and materials science professor at the University of California, Davis, says that increasing the lifetime of organic solar cells is now the biggest challenge. Solarmer's panels have a lifetime of up to three years.
"The 7.9 percent reported efficiency record is really amazing," Moulé says. "If organic photovoltaic units of more than 5 percent power efficiency could be made that have a guaranteed lifetime of over five years, then I think that they will be competitive with CIGS and silicon because of reduced panel cost."
A new polymer film protects panels from water so they can last for decades.
A new method will reduce the cost and complexity of manufacturing.
A layer of optical fiber bristles doubles the performance of organic solar cells in tests.
In what location was the 3 year rating determined? Because if it is in California, then it will last half as long in the tropics.
They are talking like stretching the lifetime to 5 years would be a breakthrough. Replacing your solar roof every 5 years? No thanks, not even close -- they need at least 3X to be in the ballpark. Especially given that the reported efficiency and lifetime are probably for lab samples where the whole engineering team put in the hours to make that one thing work. Shave off 20% in real life use. Not ready for prime time, wish them luck though.
If you really want to help with a break-through in solar cell efficiency, then join World Community Grid. It is a grid-computing project that has many projects to choose from. One of them is called "Clean Energy". They are researching different organic materials to find out which would be the best to use in a solar cell. With the material being organic the researchers are hoping to be able to build an extremely cheap yet very effecient solar cell. I run WCG on all my home computers and have selected that project as well as many others.
Not emphasized here is another use for polymer PV. Wireless indoor power. Unlike silicon, polymer OV can effectively harvest artificial and filtered indoor lighting, allowing for more wireless gizmos around the house.
That is a great idea. It is mind boggling to think of the opportunity which lies here.
Instead of being cheap, the environmental way also needs to take into consideration, therefore among energy-environment-economics can be moving concurrently.
-gede widia pratama adhyaksa-
Re: Economically efficient ways
adhyaksa,
Is that quote in Sanskrit?
Could you give us a translation?
Plastic Solar Cells Can Power Mobiles
I recently read a blog on the closing of a solar panel facility by BP in Maryland. Plastic Solar Cells lend themselves to continuous web manufacturing and as such lend themselves to a high degree of automation and quality control. This may help keep manufacturing in the USA. It will also drive the design of a new line of innovative products. I have suggested an inflatable personal mobile using plastic solar cells.
http://dancrissco.wordpress.com/2009/11/25/solar-power-plastic-inflatable-personal-electric-mobile/
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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RD
212 Comments
life expectancy
What is the efficiency over those 3 years? We need a better cost comparison, such as a net present value. If the production curve starts downward right after use, then the plastic sheeting concept isn't viable. The manpower to install and replace, and to recycle the deteriorated components also adversely affect short life plastic solar cells.
What is the longevity comparison between silicon cells?
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