When the researchers tested the cells under light filtered to match an ocean depth of about 10 meters, they were remarkably efficient, converting about 35 percent of that light energy to electricity. (Silicon solar panels are generally closer to 20 percent efficiency.)
Power in the water
After building a proper little solar panel by sandwiching the perovskite in some protective layers, the team ran real-world durability tests. First, they submerged it in seawater (using their filtered light) for about 40 days, at which point it was still at 99.6 percent of its original efficiency. Based on that, they estimate it should last 5.5 years in seawater before it drops to 80 percent—what is typically considered its useful lifetime. While terrible compared to silicon, it’s well beyond what most perovskites have achieved.
They also tested a panel in the South China Sea, attaching it to a small vehicle that could maintain a specific depth and position. The panel charged some coin cell batteries for a couple of hours each at 2, 6, and 10 meter depths. There were no surprises in performance beyond noticing that power fluctuated pretty strongly at 2 meters thanks to sunlight interacting with the surface waves. At the deeper depths, the increased scattering made the light hitting the solar panel much more consistent, though dimmer. At 10 meters, it produced a little less than a quarter as much energy as it did at 2 meters.
The researchers say their design could enable “autonomous marine power systems and submerged Internet of Things infrastructure”—think uncrewed underwater vehicles and sensors, for example. Of course, if you go much deeper, there won’t be enough light to work with. Birdman is still on his own down there.
Joule, 2026. DOI: 10.1016/j.joule.2026.102672 (About DOIs).
