A new way of making solar cells promises a cheaper way to generate electricity from the sun and new ways to integrate solar power into other products.
Solar cells, or photovoltaics, are widely made using wafers of silicon that are stiff and brittle. California Institute of Technology physics professor Harry Atwater is making photovoltaics differently.
"Our technology uses 50-100 times less silicon," he said, "in the form of a sparse array of wires. And that sparse array of wires has exactly the same light absorption and electricity-collection properties as the conventional silicon wafer cell."
The tiny silicon wires stick up from the base, or substrate, looking something like a microscopic hair brush. And because the key component of solar cells is an expensive, highly purified form of silicon, there's a real economic benefit to this design.
"So what that means is, in terms of cost, is you can use 100 times less silicon. And that's potentially very significant."
But the silicon is what converts light into electricity, so you might think using so much less silicon would reduce the electrical output, but Atwater says that's not the case.
"The light comes in and is both directly absorbed by the wires, and some of the light bounces around in between the wires. And that bouncing around or multiple scattering in between the wires results in dramatically enhanced absorption," Atwater explained. "In fact, the absorption enhancement that we see is in the range of 20 to 50 times the single-pass absorbance."
New Way of Making Solar Cells Promises Cheaper Power | Science and Technology | English
