Black Silicon Solar Cells

Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) discovered a new technique that not only enables solar cells to absorb more sunlight but it also reduces the manufacturing time and cost. They achieved all of this by etching a trillion of tiny holes into a silicon wafer the size of a compact disc. These wafers aren’t really black: they just look black because none or very little sunlight is reflected into our eyes, doing a much better job at absorbing sunlight than a solid surface does.

“By mixing gold and chemicals into a cocktail and spraying it on silicon, they were able to create a black silicon wafer in under 3 minutes at room temperature. At 100 degrees Fahrenheit they can do it in less than a minute — this bodes well for mass manufacturing.”, Brit Liggett ( Inhabitat )

But not only the process is faster and cheaper and makes more efficient silicon solar cells, it is also more eco-friendly:

“The technology would replace a process that uses dangerous silane gas, as well as cleaning gases such as nitrogen trifluoride, which has 17,000 times more punch than carbon dioxide in contributing to global warming. A switch to the black silicon wet etch technology would mean huge reductions in greenhouse gases, and improvements in the energy payback for resulting PV devices. It also reduces the capital costs of starting a factory line by about 10 percent, because it replaces several expensive vacuum vapor tools with a simple wet bath, Goodrich said”, Bill Scanlon ( NREL NEWS )

Could black become the new green?

Find out more:

http://www.nrel.gov/features/20100902_silicon.html

http://inhabitat.com/2010/09/03/new-black-silicon-solar-cells-are-cheap-and-absorb-more-sun/

http://www.treehugger.com/files/2008/10/black-silicon-sionyx-solar-power-technology-breakthrough.php