Researchers at the University of Oxford are looking to Perovskite to create a next-generation thin-film photovoltaic device. The technology has already produced test cells that are 15 percent efficient at converting sunlight into electricity.
Previous research into using Perovskite, a calcium titanium oxide mineral, had looked into creating nanostructured solar devices using complex structures and chemicals, but now Oxford Physicist Henry Snaith and his colleagues have found an easier way to make efficient cells using the technology. “We show that nanostructuring is not necessary to achieve high efficiencies with this material: a simple planar heterojunction solar cell incorporating vapor-deposited Perovskite as the absorbing layer can have solar-to-electrical power conversion efficiencies of over 15 percent (as measured under simulated full sunlight),” Snaith and his team wrote in the abstract of the research published in the Journal Nature (Sept. 11).
The researchers published their work under the title “Efficient planar heterojunction perovskite solar cells by vapor deposition.”
Vapor depositing technologies are used in other types of thin-film solar manufacturing because it can be performed at low temperatures and doesn’t need a vacuum or other expensive technologies, significantly lowering the cost of producing the technologies. Since thin-film PV is less efficient than silicon PV or multi-junction gallium arsenide-based PV (the most expensive PV technology but also the most efficient—Sharp currently has the efficiency record at 44.4 percent, according to the National Renewable Energy Laboratory), the technologies aren’t currently as desirable as silicon PV (some companies are now producing modules more than 20 percent efficient at converting sunlight to electricity), which keeps coming down in price.
Researchers previously had thought that Perovskite was not a good semiconductor. As such, it was usually paired with other layers: Perovskite would absorb the sunlight but other structures would convert the sunlight into usable electricity. This latest research has found that Perovskite is a decent semiconductor on its own and that these other structures aren’t needed for the device to produce electricity at higher efficiency and voltages.
With the research, Science, quoting Snaith, reported that Perovskite-based thin-film photovoltaics could create significantly less expensive PV devices.
“Perovskite cells now have a greater chance of hitting the mainstream market—possibly for as little as $0.15 per watt, or one-quarter the price of thin-film silicon devices.”