Perovskite solar cells are rapidly catching up with their silicon predecessors in efficiency, but still lag behind in production speed, according to foreign media reports. Now, researchers at Stanford University have developed a new way to make perovskite solar cells at speeds of up to 40 feet (12 meters) per minute, faster even than silicon.
Silicon has dominated the market for solar cells for decades, but in recent years that crown has threatened to be taken away. The fastest-growing new product is perovskite, whose efficiency rose from less than 4% in 2009 to 20% earlier this year-close to 25% of silicon. It could also be cheaper and more energy efficient to produce than silicon.
Of course, perovskites aren't perfect. It is not nearly as stable as silicon, so mass production is manual, and defects often occur during production that cause cells to degrade faster in the element. Now, researchers from Stanford University claim to have developed a way to mass-produce stable perovskite batteries at realistic speeds.
The team calls their new method the rapid spray plasma process. The process is carried out by a machine with two nozzles -- the first spraying a liquid mixture of perovskite precursors onto a sheet of glass, and the second spraying a liquid with plasma that quickly transforms it into a film of perovskite.
By using this method, perovskite membranes can be generated at a rate of 40 feet per minute, the team says. It should also be much cheaper to produce -- the researchers estimate the module costs about $0.25 per square foot, or about one-tenth the price of silicon.
"We achieved the highest throughput of any solar technology," said Nick Rolston, co-author of the study. "You can imagine putting large glass panels on rollers to continuously produce layers of perovskite at an unprecedented rate."
The efficiency of the final product is also impressive, at about 18%, and the module is still 15.5% efficient after five months of continuous use. The team says the next major hurdle for perovskite is finding a way to ensure the battery lasts a more efficient length of time.