Researchers at the University of Bath have applied a waterproof graphite-based coating to a perovskite cell intended to power the production of hydrogen underwater. The cell reportedly worked underwater longer than expected, and may open the door to a cheap and sustainable way of making hydrogen fuel from water using sunlight.

“The coated cells worked underwater for 30 hours – ten hours longer than the previous record,” the scientists wrote, adding the glue sandwiching the coat to the cells began to fail after 30 hours. They believe stronger glue could help the cell stabilize for longer. “We achieve a record stability of 30h in aqueous electrolyte under constant simulated solar illumination, with currents above 2 mA cm−2 (milliamperes per cm−2) at 1.23 VRHE,” they added.

Researchers at the Eindhoven University of Technology in the Netherlands have found a way to address the issue of stability in perovskite solar cells by adding a small amount of fluoride during the production process, which was found to increase the stability of such cells.

Fluoride stablizes perovskite solar cells by encouraging the formation of strong hydrogen bonds and ionic bonds on the surface of the perovskite material.

The scientists found the fluoride ions form a protective layer around perovskite crystals, preventing the ill effects of light, heat and moisture. "Our work has improved the stability of perovskite solar cells considerably," said Shuxia Tao, assistant professor at Eindhoven University of Technology's Center for Computational Energy Research. "Our cells maintain 90% of their efficiency after 1,000 hours under extreme light and heat conditions. This is many times as long as traditional perovskite compounds. We achieve an efficiency of 21.3%, which is a very good starting point for further efficiency gains."