Northwestern University researchers have made significant progress in extending the lifespan of perovskite solar cells with a new protective coating. The innovation could enhance the practicality of these cells for broader applications.

Perovskite solar cells, known for their efficiency and lower cost compared to traditional silicon cells, have been limited by stability issues. Typically, ammonium-based coatings are used to improve efficiency but degrade under environmental stress. The team at Northwestern has developed a more robust amidinium-based layer that is ten times more resistant to decomposition than conventional coatings.

The new coating triples the time it takes for a cell's efficiency to drop to 90% of its initial value when exposed to harsh conditions. "The field has been working on the stability of perovskite solar cells for a long time," said Bin Chen from Northwestern, who co-led the study. "By improving the protective layer, we were able to enhance the solar cells’ overall performance."

Mercouri Kanatzidis, also from Northwestern and co-leader of the study, highlighted that this advancement addresses one of the critical barriers to widespread adoption: "By chemically reinforcing the protective layers, we’ve significantly advanced the durability of these cells without compromising their exceptional efficiency."

The research involved converting unstable ammonium ligands into more stable amidinium ones through a process called amidination. This conversion prevented degradation over time, particularly under extreme heat.

The resulting solar cell achieved an impressive 26.3% efficiency and retained 90% of its initial efficiency after 1,100 hours under harsh conditions. Ted Sargent noted that perovskite-based solar cells could significantly contribute to decarbonizing electricity once design and durability are finalized.

This study aligns with Northwestern's commitment to developing high-efficiency multi-junction solar cells as part of its Generate pillar within the Trienens Institute Six Pillars of Decarbonization. The research was supported by various institutions including First Solar and the U.S. Department of Energy.

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