Shedding light on optimal materials for harvesting sunlight underwater. There may be many overlooked organic and inorganic materials that could be used to harness sunlight underwater and efficiently power autonomous submersible vehicles, report researchers. New research develops guidelines for optimal band gap values at a range of watery depths, demonstrating that various wide-band gap semiconductors, rather than the narrow-band semiconductors used in traditional silicon solar cells, are best equipped for underwater use. Source 5e.
Although as interesting as this may sound; I'd think that there could be other more useful ways to gain energy than trying to find a long distance or alternate ways to capture sunlight. Perhaps there may be energy sources at the deepest, darkest depths of the ocean that may prove more useful for future technology?