Better Plan, Wisconsin

It surprises people to learn that Germany leads the world in the use of solar energy. Even when clouds cover the sky, solar power is there. It's as reliable as the sunrise. And huge progress is being made in solar technology every day.

While industrial-scale wind turbines keep getting bigger-- from forty stories tall to fifty-- require more infrastructure in the form of power lines and sub-stations, require more land or off shore area to be disrupted, rely on fossil fuel burning power plants to function, and remain unreliable as the wind, solar power is getting smaller, more nimble, and able to be used right on site.

Because on-site energy production means lower profits for power companies, they won't see this as good news.... but we thought you might!

Scientists develop solar cells with a twist

By Julie Steenhuysen

CHICAGO (Reuters) - U.S. researchers have found a way to make efficient silicon-based solar cells that are flexible enough to be rolled around a pencil and transparent enough to be used to tint windows on buildings or cars.

The finding, reported on Sunday in the journal Nature Materials, offers a new way to process conventional silicon by slicing the brittle wafers into ultrathin bits and carefully transferring them onto a flexible surface.

"We can make it thin enough that we can put it on plastic to make a rollable system. You can make it gray in the form of a film that could be added to architectural glass," said John Rogers of the University of Illinois at Urbana-Champaign, who led the research.

"It opens up spaces on the fronts of buildings as opportunities for solar energy," Rogers said in a telephone interview.

Solar cells, which convert solar energy into electricity, are in high demand because of higher oil prices and concerns over climate change.

Many companies, including Japanese consumer electronics maker Sharp Corp and Germany's Q-Cells are making thin-film solar cells, but they typically are less efficient at converting solar energy into electricity than conventional cells.

Rogers said his technology uses conventional single crystal silicon. "It's robust. It's highly efficient. But in its current form, it's rigid and fragile," he said.

Rogers' team uses a special etching method that slices chips off the surface of a bulk silicon wafer. The sliced chips are 10 to 100 times thinner than the wafer, and the size can be adapted to the application.

Once sliced, a device picks up the bits of silicon chips "like a rubber stamp" and transfers them to a new surface material, Rogers said.

"These silicon solar cells become like a solid ink pad for that rubber stamp. The surface of the wafers after we've done this slicing become almost like an inking pad," he said.

"We just print them down onto a target surface."

The final step is to electrically connect these cells to get power out of them, he said.

Adding flexibility to the material would make the cells far easier to transport. Rogers envisions the material being "rolled up like a carpet and thrown on the truck."

He said the technology has been licensed to a startup company called Semprius Inc in Durham, North Carolina, which is in talks to license the technology.

"It's just a way to use thing we already know well," Rogers said.