A new solar cell uses tin instead of lead to harvest light.
The new method is cheap and efficient, a Northwestern University news release reported.
"This is a breakthrough in taking the lead out of a very promising type of solar cell, called a perovskite," said Mercouri G. Kanatzidis, an inorganic chemist, said in the news release. "Tin is a very viable material, and we have shown the material does work as an efficient solar cell."
The new technology employs a structure called perovskite that is made from tin instead of lead. Lead perovskite works at about 15 percent efficiency and the researchers believe the tin version will be able to match that.
The researchers "synthesized and analyzed" the material and are now working to create a solar cell.
"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," nanoscientist Robert P. H. Chang a professor of materials science and engineering at the McCormick School of Engineering and Applied Science, said in the news release.
The solid-state tin cell had an efficiency of about six percent. The material can "absorb most of the visible light spectrum, and the perovskite salt can be dissolved, and it will reform upon solvent removal without heating," the news release reported.
"Other scientists will see what we have done and improve on our methods," Kanatzidis said. "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."
Perovskite solar cells were invented in 2008; these new tin solar cells could be cheaper to make.
"Solar energy is free and is the only energy that is sustainable forever," Kanatzidis said. "If we know how to harvest this energy in an efficient way we can raise our standard of living and help preserve the environment."
