NRL scientists develop solar cell that works under water

According to NRL, underwater autonomous systems and sensor platforms are severely limited by the lack of long-endurance power sources.

To date, these systems must rely on onshore power, batteries or solar power supplied by an above-water platform.

Attempts to use photovoltaics have had limited success, primarily due to the lack of penetrating sunlight and the use of solar cells optimised more towards the unimpeded terrestrial solar spectrum.

In a statement, Phillip Jenkins, head of the NRL Imagers and Detectors Section, said: ‘The use of autonomous systems to provide situational awareness and long-term environment monitoring under water is increasing.

‘Although water absorbs sunlight, the technical challenge is to develop a solar cell that can efficiently convert these underwater photons to electricity.’

Even though the absolute intensity of solar radiation is lower under water, the spectral content is narrow and lends itself to high conversion efficiency if the solar cell is well matched to the wavelength range.