The National Renewable Energy Laboratory has expanded the license it gave New Jersey-based Natcore Technology to develop its black silicon.

The term “black silicon” refers to the seeming color of the solar cell. The dark color allows the cells to absorb more sunlight and convert more into electricity, increasing the energy output and effective efficiency of the average silicon solar cell.

Natcore has been working on NREL’s solar technology about a year, using its own patented liquid-phase deposition process to develop NREL’s black silicon.

NREL’s latest contribution to the undertaking is a patent that will allow Natcore to use less expensive copper nanoparticles instead of gold or silver in the etching process. “It takes very little material anyway,” said Natcore president and CEO Chuck Provini. “But gold and silver are much more expensive. And we think it’s pretty cool because we’ve been experimenting with copper anyway.”

The license might not make a significant difference now, when researchers are working on a smaller scale. But it’s important to develop the solar cells with the same technology in research and development that will be used when its produced on a larger scale and the cost difference between gold and copper will make a significant difference to the end user.

Natcore raised $2.5 million through private stock offerings a month ago with plans to do the needed next steps in research and development before commercializing NREL's black silicon.

Provini said researchers were working at two different labs to identify the best junction depth for the solar cell. “They’re doing that right now,” Provini said. “I think we’re going to see results really soon, pick a winner and make a solar cell.”

He said the next steps after that will be a third-party verification, then building the approved solar cell into a solar module. “We’re really in final stages now,” Provini said. “We’re pretty close."