Swiss research group develops methylammonium-free perovskite cells

A group of researchers from Switzerland's Adolphe Merkle Institute (AMI) at the University of Fribourg has developed a methylammonium-free perovskite solar cell with the same levels of efficiency of cells based on perovskite containing methylammonium (MA) molecules.

According to a paper published in the journal Science, the scientists have replaced the thermally unstable MA molecules with inorganic elements such as rubidium and cesium, thus obtaining more optimal bandgaps and stable perovskites. MA remains a principled risk factor for long-term stability and should thus be avoided, as the industry cannot afford the long-term risk factor of MA, they claim.

“These new perovskites can also harvest more sunlight, meaning they are more efficient and therefore more profitable,” said Michael Saliba, the photovoltaics group leader at AMI. The scientists developed the new cells on a planar architecture, while also improving improving perovskite interfaces through polymeric buffer layers.

The cells developed by the AMI research team have an efficiency of 20.35%. “This is one of the highest for MA-free perovskites, with a drastically improved stability reached without the stabilizing influence of mesoporous interlayers,” the scientists also explained.

“With small additional improvements, perovskite solar cells can become a commercial reality within a short time,” they added.