March 12, 2008 3:00 AM PDT

'Printed' solar cells coming to windows, clothing

Posted by Martin LaMonica

NEW YORK--Solar company Konarka wants to bring plastics to life with the sun.

Konarka has developed technology to create rolls of plastic that can convert light to electricity--a design that will result in solar power being embedded in everything from flashing Coke bottles to wireless sensors, the company claims.

Earlier this month, Konarka said that it has demonstrated the use of inkjet printing to manufacture its solar cells. And at a recent investor conference here, chairman and founder Howard Berke described Konarka's longer-term plans to embed small solar plastic cells in hundreds of products.

In the second half of this year, Berke said, Konarka will make its first shipments to customers and will announce the location of a factory.

Konarka's roll-to-roll manufacturing creates solar cells on plastic.

(Credit: Martin LaMonica/CNET Networks)

Initially the company intends to make portable solar chargers for gadgets as well as self-powered sensors, lights, and smart cards. Farther down the road, it plans to make solar windows and power-generating cloth.

In four years, Berke said, the company intends to have products for the building-integrated photovoltaics (PV) market with "bifacial cells," for placement on windows, that can convert electricity from both sides.

It is also working on a project, sponsored by the Department of Defense, to make fibers that can be woven into clothing, he said.

"You'll be able to wear, carry, integrate PV," said Berke. "Wherever plastics occur, you'll have PV."

But some solar industry watchers have become skeptical about whether this technology will ever live up to its promise. Konarka, founded in 2001, has raised several rounds of capital and taken government grants but still doesn't have a commercial product.

Plastic solar cells have the advantage of being flexible, unlike traditional silicon, but they're not nearly as efficient as rooftop panels.

Konarka's cells, which are made with a roll-to-roll manufacturing process, convert about 5 percent of the light that hits them into electricity, whereas typically solar panels with silicon cells are 16 percent to 20 percent efficient.

But its organic photovoltaic cells can convert low light, can be tuned for specific wavelengths, and can work even when the light hits at a low angle, Berke said.

"We see this as next-generation thin-film PV technology and not competing with silicon," he said.