Wednesday, 18 Sep 2019

Researchers find more stable perovskite solar cells

By exchanging the organic methylammonium (MA) with inorganic elements, the researchers have shown it is possible to avoid these unstable compounds while maintaining similar high efficiency

12 Oct 2018 | Editor

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 commercialisation. The results of their work have been published in Science.

The research was carried out by Group Leader Dr. Michael Saliba at AMI. The group's focus the problem of the highly volatile and heat-sensitive methylammonium (MA) molecule.

According to the researchers perovskites have the material properties to become a serious contender for inexpensive solar energy production. The biggest roadblock to achieving this potential is the long-term stability of perovskite-based devices.

The researchers say 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 inorganic elements, 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.

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

"These new perovskites can also harvest more sunlight, meaning they are more efficient and therefore more profitable."

"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."

Dr. Michael Saliba, Group Leader at AMI

Methylammonium-free, high-performance and stable perovskite solar cells on a planar architecture

Silver-Hamill Turren-Cruz | Anders Hagfeldt | Michael Saliba

Science 11 Oct 2018: | eaat3583 | DOI: 10.1126/science.aat3583


Currently, perovskite solar cells (PSCs) with high performances >20% contain Br, causing a suboptimal bandgap, and the thermally unstable methylammonium (MA) molecule. Avoiding Br and especially MA can, therefore, result in more optimal bandgaps and stable perovskites. We show that inorganic cation tuning, using Rb and Cs, enables highly crystalline formamidinium-based perovskites without Br or MA. On a conventional, planar device architecture, using polymeric interlayers at the electron and hole transporting interface, we demonstrate an efficiency of 20.35% (stabilized), one of the highest for MA-free perovskites, with a drastically improved stability reached without the stabilizing influence of mesoporous interlayers. The perovskite is not heated beyond 100°C. Going MA-free is a new direction for perovskites that are inherently stable and compatible with tandems or flexible substrates which are the main routes commercializing PSCs.


About Adolphe Merkle Institute - University of Fribourg

Source: Adolphe Merkle Institute - University of Fribourg

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