New Solar Cells Can Generate Power Underwater

Researchers at Yunnan University, led by Simin Ma, have created perovskite solar cells specifically engineered to generate electricity underwater, offering a potential new power source for marine sensors and autonomous underwater equipment. Perovskite solar cells differ from traditional silicon panels, as they can be chemically adjusted to capture specific wavelengths of light.

This advantage becomes crucial underwater, where water naturally blocks many wavelengths that silicon panels rely on. The research team successfully achieved an impressive 35% efficiency under simulated underwater conditions. This is markedly higher than the 20% typical efficiency of conventional silicon solar panels, although the measurements are taken under differing lighting conditions.

To enhance durability underwater, the team incorporated an additive known as polyhexamethylene guanidine hydrochloride. This component works by creating a water-resistant barrier and refining the perovskite crystal structure. The result is both improved resistance to degradation and enhanced electrical performance. After 40 days of testing submerged in seawater, the cells retained an astounding 99.6% of their initial efficiency.

This suggests a lifespan of roughly 5.5 years before the panels lose 80% of their initial performance, a significant improvement over conventional silicon panels.

To validate the technology, the researchers conducted field tests in the South China Sea. They attached a panel to a small underwater vehicle and observed it successfully charging coin-cell batteries for extended periods at depths of 2, 6, and 10 meters. The power output varied at two meters due to wave action altering sunlight exposure.

At greater depths, the decreasing sunlight visibility led to reduced but steadier power generation. At the 10-meter depth, the panel produced about a quarter of the energy it generated at two meters.

The researchers are optimistic about the potential of this technology to power autonomous marine systems, underwater Internet of Things devices, sensors, and unmanned underwater vehicles. However, they acknowledge that the technology's effectiveness is limited at greater depths, where insufficient sunlight penetrates the water to make solar generation practical.