Researchers from the Adolphe Merkle Institute (AMI) at the University of Fribourg have developed a new type of more stable, highly efficient next-generation perovskite solar cell, opening perspectives for future commercialization. The results of their work have been published in the top-ranked journal Science.

Researchers are increasingly turning their efforts towards perovskite solar cells, one of the most promising developments for photovoltaic energy. Despite their novelty, the efficiency of perovskite solar cells is already approaching the ubiquitous silicon solar cells. The biggest roadblock to achieving this potential is long-term stability of perovskite-based devices.

The research was carried out by Group Leader Dr. Michael Saliba at AMI. This time, the problem of the highly volatile and heat-sensitive methylammonium (MA) molecule was addressed. The most efficient perovskite solar cells contain unstable methylammonium (MA) molecules, mainly because of their capacity to provide high-performance values.

By exchanging the organic MA with the inorganic elements rubidium and cesium, the researchers have shown it is possible to avoid these unstable compounds while maintaining similar high efficiency. This allows for more stable solar cells, which is a key step towards eventual commercial use.

“These new perovskites can also harvest more sunlight, meaning they are more efficient and therefore more profitable,” explains Saliba. “In addition, these new materials are compatible with flexible substrates, making them useful for a wide variety of applications.”

“Essentially, this sets perovskites on the path of becoming a profitable, long-term solution for a sustainable energy future. With small additional improvements, perovskite solar cells can become a commercial reality within a short time.”

The results were published on October 11 in Science.

This study was carried out in collaboration with the Hagfeldt group (Laboratory of Photomolecular Science) at the Federal Institute of Technology in Lausanne (EPFL).

Reference:

Silver-Hamill Turren-Cruz, Anders Hagfeldt, Michael Saliba, Demonstrating methylammonium-free, high-performance and stable perovskite solar cells on a planar, low-temperature architecture. Science. 11 October 2018.