Coming soon: A better, poison-free solar cell

Sure, solar power is clean and green, but to make it more efficient, researchers have had to use some nasty stuff. Until now.

Eric Mack Contributing Editor
Eric Mack has been a CNET contributor since 2011. Eric and his family live 100% energy and water independent on his off-grid compound in the New Mexico desert. Eric uses his passion for writing about energy, renewables, science and climate to bring educational content to life on topics around the solar panel and deregulated energy industries. Eric helps consumers by demystifying solar, battery, renewable energy, energy choice concepts, and also reviews solar installers. Previously, Eric covered space, science, climate change and all things futuristic. His encrypted email for tips is ericcmack@protonmail.com.
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Eric Mack
2 min read

These cells could soon get smaller, and without any toxic, brain-damaging elements. GE

New research seems to indicate that we can have more solar power without that pesky, toxic lead that's been used to boost efficiency in the lab in recent years.

Solar power has long been one of the darlings of the environmental movement, given its endless supply of energy that can be harvested by simply plunking down a photovoltaic panel under a sunny sky. Of course, we don't have an endless supply of roof space and empty desert floor on which to place those big clunky panels.

This makes efficiency a kind of holy grail for those in the photovoltaic world. In recent years, new solar cells that use what's called a perovskite structure have produced some of the most promising advances in creating more efficient methods of reaping as much juice as possible from our nearest star.

There's just been one problem with the perovskite approach -- it relies on using toxic lead. So much for clean and green and not potentially causing brain damage.

But now researchers out of Northwestern University say they've developed a perovskite solar cell that uses tin rather than lead to collect energy.

"Our tin-based perovskite layer acts as an efficient sunlight absorber that is sandwiched between two electric charge transport layers for conducting electricity to the outside world," said Northwestern nanoscientist Robert P. H. Chang, who helped engineer the new type of cell, in a release from the university.

Details of the lead-free solar cell have been published in Nature Photonics.

Right now the tin cells aren't quite as efficient as lead, but the researchers are confident they have the potential.

"Other scientists will see what we have done and improve on our methods," said lead researcher Mercouri G. Kanatzidis, an inorganic chemist with the rare distinction of being something of an expert in tin. "There is no reason this new material can't reach an efficiency better than 15 percent, which is what the lead perovskite solar cell offers. Tin and lead are in the same group in the periodic table, so we expect similar results."

Excellent. I'll start lining up all my old tin cans on the roof immediately. That is how it works, right?