Coating helps solar panels soak up more sun

TROY, NEW YORK - A new type of reflective coating can make solar panels far more efficient, soaking up nearly all available sunlight from nearly any angle, U.S. researchers said.

Current solar panels — which convert energy from the sun into electricity — absorb only about two-thirds of available sunlight.

But surfaces treated with a coating developed at Rensselaer Polytechnic Institute in Troy, New York, can harvest 96.2 percent of sunlight.

"That is a tremendous savings," Rensselaer's Shawn-Yu Lin, whose study appears in the journal Optics Letters, said in a telephone interview.

Lin said the technology addresses two main problems in current solar cells. It captures more colors of solar spectrum and it captures light from all angles.

"If you look at a solar panel, it looks a bit bluish," Lin said. That is "telling you not all of the blue color is being absorbed. It should look totally dark."

The other problem is that solar panels work best when sun shines directly on them. To solve this, large solar arrays mechanically shift position throughout the day — much like sunbathers on a beach.

Lin and colleagues think they have found a better solution.

Their coating is made up of seven layers of porous material stacked in such a way that each enhances the antireflective properties of the layer below.

Together they act as a buffer zone, trapping light from all angles. "Your efficiency increases by 30 percent," Lin said.

He thinks the material could be applied to all types of solar cells.

"It's not going to require many added instruments too adopted this technology," he said.