What happens if you put solar cells underwater? To satisfy curiosity, scientists have really done such experiments.
Recently, Indian scientists tested the performance of underwater amorphous silicon solar cells by putting the cells into water. The scientists say that the cells do lose a lot of energy when submerged underwater, but that doesn't mean it's useless, and that underwater solar systems have potential for commercial and defense applications such as surveillance sensors.
Because they are underwater, solar radiation is low. But thanks to the lower temperatures, underwater solar cells are in a more ideal environment. Meanwhile, through controlled experiments with crystalline silicon solar and amorphous silicon solar, they found that the conversion efficiency of monocrystalline and polycrystalline silicon cells decreases by 20 percent at a depth of 1m underwater, but the attenuation of amorphous silicon solar cells at 1.5m underwater is still smaller than that of crystalline silicon cells, and therefore has potential development value.
Although the conversion efficiency will be reduced, but still can be sufficient to power underwater electronic devices, according to the experimenters.
The scientists used an amorphous cell coated with polydimethylsiloxane (PDMS) for the experiment. Polydimethylsiloxane (PDMS), a polymer silicone compound with good optical transparency and hydrophobic properties, is the most widely used silicon-based organic polymer material, and the coating increased the conversion efficiency of the battery by 2.79 percent at two meters underwater.
The reason for choosing amorphous silicon cells is because of the various characteristics that amorphous silicon cells have, such as low production cost, suitable for mass production, and good low light response. Amorphous silicon cells have the spectral sensitivity to absorb light, basically in the visible wavelength range of 380-780nm, and in the underwater environment, the spectrum becomes narrower with increasing depth, which makes amorphous silicon cells ideal for underwater environments.
Scientists also tested the power generation performance of amorphous silicon cells in different water environments. Four water environments were set up for the experiment: deionized water, lake water, seawater and artificial seawater (artificial seawater is prepared with sea salt with a salinity of 3.5% and other water impurities).
The worst power generation performance was obtained in lake water, where the light was weakest due to bacteria, algae and other impurities that reduced the transparency of the liquid. The best experimental power was obtained in deionized water, followed by seawater and artificial seawater.
The experimenters concluded that although there are still challenges and limitations to unfolding solar power underwater, solar power still has great potential for underwater monitoring sensor applications or other commercial and defense applications.
The report, "Results of Analyzing Solar Radiation on Amorphous Silicon Solar Cells in Different Underwater Environments," was published in the International Journal of Energy Research by a team of scientists from the Indian Institute of Technology Kanpur and Birla Institute of Technology, Birani Hyderabad Campus.
