» Page 1 of 1

In the race to make clean technologies more efficient and marketable, solar cell developer Innovalight has a breakthrough to boast of.

The Santa Clara start-up, in a joint research effort with the U.S. Department of Energy's National Renewable Energy Laboratory, has found that silicon nanocrystals, or quantum dots, can produce more than one electron from single photons of sunlight, increasing the amount of light that is converted into usable electricity.

"It really gives huge promise to super high efficiency, efficiencies that have not ever been seen in solar cells," said Conrad Burke, CEO and president of Innovalight, which was founded in 2002. "This effect, which can only be seen with these quantum dot materials, [has] the unique capability of giving multiple electrons for a single photon."

The demonstrated effect is called Multiple Exciton Generation (MEG), and was first discovered by researchers using lead particles at the DOE's renewable energy lab, based in Golden, Colo.

Aware of the existing research, Burke approached the lab two years ago and suggested a collaboration. Innovalight supplied the lab with quantum dot material that it develops in-house for its nanotechnology-based printed solar cells.

"This is very encouraging given that most of the solar cells made today, over 90 percent,  are made of silicon," Burke said.  

According to the research, the maximum theoretical efficiency of quantum dot solar cells exhibiting optimal MEG is about 44 percent with normal unconcentrated sunlight and 68 percent with sunlight concentrated by mirrors or lenses. Today's conventional solar cells that produce one electron per photon have maximum efficiencies of 33 percent and 40 percent, respectively.

Innovalight is developing solar modules that utilize silicon nano particles that are dispersed into a silicon ink that is then printed onto a substrate surface.

The company says its nanotechnology silicon platform will cut current solar technology costs by a factor of ten. The majority of solar energy cells are made from silicon wafers, which are costly and time consuming to produce. The printing method is faster and wastes less material.

Another player in the market is Nanosolar, a Palo Alto start-up with plans for new manufacturing sites for its printable solar cell manufacturing process in California and in Germany.

The MEG technology will not be utilized in Innovalight's solar cells, which are projected to be on the market in 2009, Burke said.

But the research to both the company's R&D efforts and the solar community is significant,  Burke said, "considering that today, most of the market is serviced with solar panels which average around 15 percent efficiency."

Innovalight received a Series B round of $7.5 million last year from Harris & Harris Group, Inc., and existing investors Apax Partners, ARCH Venture Partners, Sevin Rosen Funds and Triton Ventures.