Solar panels are no longer a novelty on the landscape. Small-scale energy users increasingly rely on solar energy for water heating or electric power. Yet, solar energy is far from replacing the world's energy needs due to the high cost of producing photovoltaic cells.
In a few years, however, solar energy may be the renewable solution of choice. Lawrence Berkeley National Laboratory has developed nanocrystal solar cells with the potential to bring solar energy to the marketplace at fossil fuel prices. Just one micron thick, 200 times thinner than conventional solar cells, Berkeley Lab's solar cells require significantly less crystalline silicon. They are created with a nanocrystal ink printed onto a panel, using roll-to-roll manufacturing, and then topped with glass. Solexant, the San Jose start-up with exclusive rights to the technology, plans to build a U.S.-based commercial plant to manufacture the solar cells for $0.50 per watt, about five times less than production costs for today's solar panels.
Nanocrystal solar cell efficiency will reach 12 percent Rolling Out Affordable Solar Energy by 2011 and a maximum of 25 percent once fully optimized. In addition, because the cells have no organic materials, their anticipated operating life is 25 years. Their performance can be tuned easily to increase their absorption across the spectrum from ultraviolet to visible light to infrared. Finally, the solution processing technique used to produce the solar cells is less energy intensive and potentially up to 10 times faster than the vaporphase deposition process used to manufacture typical thin-film solar cells.
With all these features plus cost-competitiveness, Berkeley Lab's technology can provide large-scale energy generation for electrical utilities and a solar power grid for refueling hybrid vehicles. In an equally impressive application, the nanocrystal solar cells can supply electricity to remote areas lacking an electrical grid. This same technology can also be applied, essentially in reverse, to produce high-efficiency LEDs.
R&D Magazine named nanocrystal solar cells one of the Top 100 New Technologies of 2009 in its annual competition. The Berkeley Lab team of inventors includes Paul Alivisatos, Delia Milliron, Ilan Gur, Liberato Manna, Erik Scher, Haitao Liu, Steven Hughes, Neil Fromer, Richard Robinson and Bryce Sadtler.
In 2008, Berkeley Lab's portfolio of nanocrystal solar cell technologies was licensed exclusively to Solexant Corporation, headed by CEO Damoder Reddy. Strong financial backing has enabled Solexant to hire staff and procure a large manufacturing space.
The company will set up a pilot manufacturing line by the end of 2009 and produce prototype cells by mid-2010—all steps towards building a 100-MW production facility scheduled to come on line in 2011. As this technology develops further, solar energy may finally become the reliable, cost-effective power source of choice.
