Iowa State University engineers, in a project partially supported by the National Science Foundation, have found a way to take advantage of perovskite’s useful properties while stabilizing the cells at high temperatures.
Vikram Dalal, an Iowa State University Professor in Engineering and corresponding author of the paper, said there are two key developments in the new solar cell technology: First, he said the engineers made some tweaks to the makeup of the perovskite material. They got rid of the organic components in the material – particularly cations, materials with extra protons and a positive charge – and substituted inorganic materials such as cesium. That made the material stable at higher temperatures.
Second, they developed a fabrication technique that builds the perovskite material one thin layer – just a few billionths of a meter – at a time. This vapor deposition technique is consistent, leaves no contaminants, and is already used in other industries so it can be scaled up for commercial production.
“Our perovskite solar cells show no thermal degradation even at 200 degrees Celsius (390 degrees Fahrenheit) for over three days, temperatures far more than what the solar cell would have to endure in real-world environments,” the team said.
When Dalal did some comparing and contrasting, he found that: “That’s far better than the organic-inorganic perovskite cells, which would have decomposed totally at this temperature. So this is a major advance in the field.”
The paper reports the new inorganic perovskite solar cells have a photoconversion efficiency of 11.8%. “We are now trying to optimize this cell – we want to make it more efficient at converting solar energy into electricity,” Dalal said. “We still have a lot of research to do, but we think we can get there by using new combinations of materials.”
As they move ahead, the engineers believe they’re on a proven path: “This study demonstrates a more robust thermal stability of inorganic perovskite materials and solar cells at higher temperatures and over extended periods of time than reported elsewhere,” they wrote in their paper. “(These are) promising results in pursuit of the commercialization of perovskite solar cell materials.”