Cheap Solar Power Emerging From Mineral Named for Russian Count

Materials that may be cheaper and more efficient than silicon at converting the sun’s rays into electricity could be key to the next generation of solar power, scientists say.

Though years away from being used to commercially produce solar cells, perovskites, named for a 19th century Russian count, are emerging as the most promising material for solar cells. Panels based on perovskites are surprising researchers by efficiently converting sunlight into electricity, according to Jenny Chase, lead solar analyst with Bloomberg New Energy Finance in London.

Perovskites are exciting “not because of where they are, but because they’re getting better really, really fast,” said Chase. “The rate of progress in the lab has been astounding.”

Most of the 52 gigawatts of solar power that was expected to be installed around the world last year will use panels made of silicon mainly derived from sand. The best silicon-based solar cells from SunPower Corp. can convert as much as 24.2 percent of sunlight to electricity.

Solar cells made from perovskite are already nearing that level. They can convert more than 20 percent of sunlight into power, according to scientists at the Korea Research Institute of Chemical Technology.

By surpassing the 20 percent conversion rate, perovskites have achieved a measure “attained by only a handful of other technologies,” according to Martin Green, a professor at the University of New South Wales in Australia. Using the material in a hybrid cell may eventually boost efficiency to more than 40 percent, Green said.

A new formula that can improve the performance of perovskite solar cells is showing promise in the lab, according to a report today in the journal Nature.

Printing Process

Solar cells using perovskite exhibited “highly improved efficiency” converting “more than 20 percent” of sunlight into electricity, Sang Il Seok, a researcher at the institute, said in an e-mail.

Perovskite cells may be produced by using a printing process, Seok said.

“We expect that fabrication cost will be reduced to below a third of silicon-based cells,” he said.

First Solar Inc., the largest U.S. photovoltaic panel manufacturer, uses cadmium telluride to produce solar panels that can convert 14.2 percent of sunlight into power.

Oxford Photovoltaics hopes to produce panels with perovskite-based solar cells in 2017, according to company co-founder and Oxford University researcher Henry Snaith. Saule Technologies in Warsaw is pursuing the same goal.

Both ventures must overcome the competitive advantage held by silicon-based panels, which have fallen more than 95 percent in price over the last decade.

Cheap Material

“You don’t just need to be efficient, you need to be cheap,” said Chase. “It doesn’t necessarily matter how efficient you are when your feedstock is free. Anything that comes in now has to come down the cost curve really fast.”

Materials needed to make perovskite-based solar cells are cheap and perform better than silicon-based technology, Snaith said in an e-mail. Perovskite-based solar cells can absorb the spectrum of light that silicon-based cells miss, meaning that a hybrid cell could convert close to 30 percent of sunlight into electricity.

The technology will be be more efficient than silicon-based solar cells “in the relatively near-term,” Snaith said.

New methods of improving solar panels may be needed as the rate of improvement in panel efficiency slowed last year, according to a Jan. 4 report from Bloomberg New Energy Finance.

Green, the professor who taught Suntech Power Holdings Co. founder and former chief executive officer Shi Zhengrong, sees potential in using materials like perovskites to create hybrid cells. While the stability of perovskites-based solar cells needs to improve, he foresees the technology being commercialized “in five years at the earliest.”

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