Although the performance of pervoskite cells is promising in lab tests, the devices still suffer from low stability. "We need solar modules that can last for at least 5 to 10 years. For now, the lifetime of PSCs is much shorter," said Dr. Longbin Qiu in the OIST Energy Materials and Surface Sciences Unit led by Prof. Yabing Qi.
The researchers replaced titanium dioxide as the electron transport layer with tin dioxide, a stronger conductor that doesn't react with the adjacent perovskite layer. They also developed a method of applying tin dioxide to produce stable, efficient and scalable cells. Using sputtering deposition, the researchers learned how to craft an effective electron transport layer from tin dioxide. By precisely controlling the power of the sputtering and speed of the deposition, the researchers produced smooth layers with a uniform thickness over a large area without damaging the perovskite layer.
In experiments, the researchers found that tin dioxide-based devices showed lifetimes over three times longer than devices using titanium dioxide with an efficiency of over 20 percent. "Tin dioxide can give users the device performance they need," said Qiu.
The researchers then built a larger 5 by 5 centimeter solar module with a light collecting area 22.8 square-centimeters, finding that the resuting devices showed over 12 percent efficiency.
"We want to scale these devices up to a large size, and though their efficiency is already reasonable, we want to push it further," said Prof. Qi. "We are optimistic that in the next few years, this technology will be viable for commercialization."
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