A relatively simple brute force manufacturing step creates solar cells at much lower cost. The big, sexy breakthroughs are great and technological leaps are fun, but a lot of the time it’s the almost mundane “a ha” moment that puts together well-known materials and processes that take a technology to the next step. This particular discovery sounds very promising since it both reduces production costs and almost retains maximum solar efficiency.
From the link:
A new low-cost etching technique developed at the U.S. Department of Energy’s National Renewable Energy Laboratory can put a trillion holes in a silicon wafer the size of a compact disc.
As the tiny holes deepen, they make the silvery-gray silicon appear darker and darker until it becomes almost pure black and able to absorb nearly all colors of light the sun throws at it.
At room temperature, the black silicon wafer can be made in about three minutes. At 100 degrees F, it can be made in less than a minute.
The breakthrough by NREL scientists likely will lead to lower-cost solar cells that are nonetheless more efficient than the ones used on rooftops and in solar arrays today.
R&D Magazine recently awarded the NREL team one of its R&D 100 awards for Black Silicon Nanocatalytic Wet-Chemical Etch. Called “the Oscars of Invention,” the R&D 100 awards recognize the most significant scientific breakthroughs of the year.
Also from the link (and conveniently making my point above about “almost mundane ‘a ha’ moment”s):
In a string of outside-the-box insights combined with some serendipity, Branz and colleagues Scott Ward, Vern Yost and Anna Duda greatly simplified that process.
Rather than laying the gold with vacuums and pumps, why not just spray it on? Ward suggested.
Rather than layering the gold and then adding the acidic mixture, why not mix it all together from the outset? Dada suggested.
In combination, those two suggestions yielded even better results.
A silver wafer reflects the face of NREL research scientist Hao-Chih Yuan, before the wafer is washed with a mix of acids. The acids etch holes, absorbing light and turning the wafer black. Credit: Dennis Schroeder