Solar Cells Getting Thinner

Silicon-based solar cells have just gotten better as a discovery 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.

Solar cells are a part of the solar energy sector and will offer more opportunities for buildings to acquire this alternative energy. Companies such as Japanese consumer electronics maker Sharp Corp. and Germany’s Q-Cells are creating the thinner cells, but the cells 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.