To make the sheets, two high-temperature strings, or filaments, rise through a shallow crucible of molten silicon. A thin film of silicon spans the space between them, supported at the edges by the strings. “It’s like pulling a wand out of a soap solution,” Sachs said, “and the edge of the wand holds the soap film in place.” But in String Ribbon the film instantly turns solid, forming an 8-centimeter-wide silicon ribbon, just 200 microns thick.

The process is continuous. Chunks of silicon enter the furnace and melt, the strings unwind from spools, and the emerging ribbon is cut to 2-meter lengths without stopping. Each ribbon is then laser-cut into wafers, which go directly onto a belt for the next step in becoming solar cells and ultimately high-efficiency solar panels.

ake the sheets, two high-temperature strings, or

To make the sheets, two high-temperature strings, or filaments, rise through a shallow crucible of molten silicon. A thin film of silicon spans the space between them, supported at the edges by the strings. “It’s like pulling a wand out of a soap solution,” Sachs said, “and the edge of the wand holds the soap film in place.” But in String Ribbon the film instantly turns solid, forming an 8-centimeter-wide silicon ribbon, just 200 microns thick.

The process is continuous. Chunks of silicon enter the furnace and melt, the strings unwind from spools, and the emerging ribbon is cut to 2-meter lengths without stopping. Each ribbon is then laser-cut into wafers, which go directly onto a belt for the next step in becoming solar cells and ultimately high-efficiency solar panels.