Underwater Solar Cells Generate Power at 10 Meters Depth
A collaborative team of scientists from China and Switzerland has reportedly developed solar cells capable of functioning at depths of 10 metres underwater, potentially revolutionising the power supply for submerged sensors, cameras, and communication systems in marine environments.
In their research, published in the journal Joule, the scientists highlight that harnessing solar energy underwater poses significant challenges, particularly due to the substantial attenuation of sunlight as it penetrates water. This limitation has kept traditional solar cells restricted to very shallow depths of around two metres, hindering broader applications in aquatic settings.
Breaking New Ground in Underwater Technology
Wen-Hua Zhang, an author from Yunnan University and Southwest United Graduate School in Kunming, China, noted the scarcity of existing studies focussing on underwater solar cells, all of which typically examine shallow depths of two metres or less—a scenario that falls short of practical use cases. “This work represents the first functional validation of submerged solar cells operating effectively at depths of up to approximately 10 metres, greatly expanding their potential applications,” Zhang explained.
The team employed lead halide perovskite solar cells designed to absorb sunlight effectively at underwater depths. Initial laboratory tests demonstrated their ability to harness blue to orange light. Following 300 days of storage in an oxygen-free environment, the solar cells retained approximately 96 per cent of their original efficiency. They also exhibited minimal degradation after enduring 1,160 hours of simulated conditions mimicking a depth of 10 metres.
Field Tests Demonstrate Promising Results
Taking their research beyond the lab, the team submerged the solar cells in underwater robots near the Weizhou Islands in the South China Sea. Once deployed at a depth of 10 metres, these cells demonstrated “exceptional” long-term operational stability.
Zhang expressed surprise at the amount of electrical energy generated by their large-area modules during real-world conditions at this depth after just two hours of exposure. “Moreover, we have successfully scaled from small laboratory cells to larger modules, providing compelling evidence for the viability of underwater photovoltaics,” he stated.
The next steps for Zhang’s team include testing the perovskite solar cells at greater depths to ascertain the operational limits and to develop standardised protocols for assessing underwater solar technologies.
Expanding the Horizons of Solar Energy
While much of the current focus in solar photovoltaic (PV) electricity generation remains centered on reducing reliance on fossil fuels on land, the researchers assert that there are significant opportunities for solar cells to serve practical purposes offshore. Applications such as aquaculture monitoring and offshore communication systems could greatly benefit from the emergence of submerged solar power generation.
