Grist has an article on the progress of plastic solar cells - Fantastic solar plastic breakthrough.

One of the holy grails of solar power has been to create very thin plastic solar cells that could be attached to just about anything to generate electricity -- windows, awnings, bus shelters.

You can find very low-powered flexible panels embedded in backpacks and small solar chargers, but the challenge has been to increase the efficiency of such photovoltaic cells. Now a company that has spent years developing an organic solar technology, Konarka of Lowell, Mass., says its "Power Plastic" has set a new record, achieving a 8.3 percent efficiency rate in converting sunlight into electricity. The National Renewable Energy Laboratory certified the efficiency rating.

"This unsurpassed NREL certification opens new doors for the commercial production of cost-effective, efficient electricity for numerous large scale applications," Howard Berke, Konarka's chief executive, said in a statement.

Now, 8.3 percent is less than half the efficiency of a conventional crystalline silicon photovoltaic panel like those found on residential rooftops. But it's a notable achievement for a solar cell that uses organic molecules to generate electricity. The great promise of organic molecules is that they can be produced at far less cost than standard silicon solar panels, but the low efficiency of organic photovoltaics has limited their use. ...

A couple of years ago, a Konarka executive showed me just how portable and easily installed photovoltaic plastic can be. He pulled a roll of solar modules out of a briefcase and unfurled them on a table. Within a few minutes they were powering a lamp.

If you happen to be in San Francisco, you can spot Power Plastic modules at bus stops. The modules are embedded in the wave-shaped red roofs of the bus shelter and power its lights, as well as Wifi routers for web-surfing passengers.

The city plans to solarize 300 bus stops, which would generate 43,000 kilowatt-hours a year.

Now that's fantastic plastic.

Technology Review has an article on research into improving the efficiency of plastic solar cells - Giving Plastic Solar Cells an Energy Boost.

If the efficiency of polymer solar cells--which are cheaper and lighter than silicon cells--can be boosted significantly, they could be ideal for plastering on rooftops or laminating on windows.

Solarmer Energy, based in El Monte, CA, is on target to reach 10 percent efficiency by the end of this year, says Yue Wu, the company's managing director and director of research and development. Organic cells will likely need at least that efficiency to compete on the photovoltaic market.

In collaboration with Luping Yu, a professor at the University of Chicago, the startup has previously engineered polymers that absorb a broad range of wavelengths and has made cells that convert sunlight to electricity with a record efficiency of nearly 8 percent.

Polymer solar cells with even higher efficiencies are in the works. Solarmer is collaborating with Yang Yang, a materials science and engineering professor at the University of California, Los Angeles. Yang is working on a stack of multiple cells that absorb different bands of light. He expects to achieve 12 to 15 percent efficiencies using this approach along with new polymers and better device design. So far, he has made laboratory prototypes that are better than 6 percent efficient.

Polymer solar cells should be cheaper to make than thin-film cadmium-telluride or copper indium gallium selenide (CIGS) ones because they use low-cost materials that are easy to print, says Michael McGehee, a materials science and engineering professor at Stanford University. But McGehee believes polymer cells will need to be more than 15 percent efficient to have a major impact on the solar power market. "We still don't understand the physics well enough to know what the theoretical limit is," McGehee says. "I think cells with 15 to 20 percent could be possible."

GE has confirmed long-standing speculation that it plans to make thin-film solar panels that use a cadmium- and tellurium-based semiconductor to capture light and convert it into electricity. The GE move could put pressure on the only major cadmium-telluride solar-panel maker, Tempe, AZ-based First Solar, which could drive down prices for solar panels.

Last year, GE seemed to be getting out of the solar industry as it sold off crystalline-silicon solar-panel factories it had acquired in 2004. The company found that the market for such solar panels--which account for most of the solar panels sold worldwide--was too competitive for a relative newcomer, says Danielle Merfeld, GE's solar technology platform leader.

She says cadmium-telluride solar is attractive to GE in part because, compared to silicon, there's still a lot to learn about the physics of cadmium telluride, which suggests it could be made more efficient, which in turn can lower the cost per watt of solar power. It's also potentially cheaper to make cadmium-telluride solar panels than it is to make silicon solar cells, making it easier to compete with established solar-panel makers. Merfeld says GE was encouraged by the example of First Solar, which has consistently undercut the prices of silicon solar panels--and because of this has quickly grown from producing almost no solar panels just a few years ago to being one of the world's largest solar manufacturers today.

Technology Review has an article on plastic solar cells with "near-perfect internal efficiency" - Pushing Plastic Solar Cells.

Plastic solar cells are lightweight, flexible, and, most important, cheap to make. But so far, these devices have been too inefficient to compete with silicon solar cells for most applications. Now researchers from a few institutions claim to have made polymer solar cells with record-breaking efficiencies. These cells still aren't good enough to compete with silicon, but polymer efficiencies have been increasing at a rate of about 1 percent a year. If they can keep this up, say researchers, plastic solar cells will be competing with silicon within a few years.

This week, in the online edition of Nature Photonics, researchers reported on polymer solar cells that convert about 6.1 percent of the energy in sunlight into electricity--inching a bit closer to the 10 percent that they say will be needed to gain a significant foothold in the market. (Conventional silicon cells are about 15 percent efficient.) The new efficiency numbers "show that we're in the game," says Alan Heeger, a professor of physics at the University of California, Santa Barbara, who led the research. Heeger shared the Nobel Prize in Chemistry in 2000 for his role in the development of the first conducting polymers, and he's cofounder and chief scientist at Konarka, a plastic solar cell company headquartered in Lowell, MA.

The California researchers' results compare very favorably with previous published descriptions of polymer solar cells, whose efficiency has hovered around 5 percent. Konarka says that the company's cells, which use different materials than the cells made in Heeger's university lab, have recently been rated at about 6.4 percent. And a competitor in San Mateo, CA, called Solarmer Energy has made plastic cells with similar efficiencies, according to an affiliated researcher.

Plastic solar cells, no matter how well designed, have intrinsic limits dictated by the polymers that make up their active layer. The polymers made so far can only absorb relatively narrow bands of light. It's possible to boost their power-conversion efficiency by stacking films of polymers designed to pick up different bands of light; Heeger's group has, in fact, had some success with this in the past. But this approach has a major disadvantage. "Layering is self-defeating because you increase the fabrication costs," says Luping Yu, a professor of organic chemistry at the University of Chicago, who is also working on solar cells.