A new type of high bandgap underwater solar cell has been developed at the U.S. Naval Research Laboratory (NRL). Previously limited by the filter that water sheds on the light entering it, this gallium-indium phosphide solar cell is best suited for this type of application.
GaInP solar cells are highly efficient in light whose wavelength varies from 400 to 700 nanometers and work well in low-light conditions. This invention will benefit underwater autonomous systems and sensor platforms, which could break free from the connection to the on-shore grid.
“The use of autonomous systems to provide situational awareness and long-term environment monitoring underwater is increasing,” said Phillip Jenkins, head, NRL Imagers and Detectors Section. “Although water absorbs sunlight, the technical challenge is to develop a solar cell that can efficiently convert these underwater photons to electricity.”
Because the water filters light and only lets the blue/green portion of the spectrum to enter, GaInP underwater solar cells are better suited because they have a higher bandgap than solar cells suited for normal lighting conditions.
The experiments that the NRL performed showed that their new underwater solar cells performed at 7 watts per square meter and that the technology can actually be used in real life conditions.