Egypt's current account gap narrows, but overall BoP records deficit    Egypt's PM reviews debt reduction strategy, eyes more private investment    Egypt hosts international neurosurgery conference to drive medical innovation    Egypt, India discuss expanding industrial, investment partnerships    World Bank proposes Egypt join new global health initiative    Egypt's EDA discusses Johnson & Johnson's plans to expand investment in local pharmaceutical sector    I won't trade my identity to please market: Douzi    Sisi sends letter to Nigerian president affirming strategic ties    Egypt welcomes 25-nation statement urging end to Gaza war    Egypt, Senegal sign pharma MoU to unify regulatory standards    Egyptian pound ticks down in early Tuesday trading    Famine kills more Gaza children as Israel tightens siege amid global outrage    Kuwait's Crown Prince, Egyptian minister discuss strengthening cooperation    Egyptian Drug Authority discusses plans for joint pharmaceutical plant in Zambia    Egypt's FM seeks deeper economic, security ties on five-nation West Africa tour    Two militants killed in foiled plot to revive 'Hasm' operations: Interior ministry    Egypt foils terrorist plot, kills two militants linked to Hasm group    Egypt, Somalia discuss closer environmental cooperation    Egypt exports 175K tons of food in one week    Giza Pyramids' interior lighting updated with new LED system    Egypt's EHA, Huawei discuss enhanced digital health    Foreign, housing ministers discuss Egypt's role in African development push    Korea Culture Week in Egypt to blend K-Pop with traditional arts    Egypt, Uruguay eager to expand trade across key sectors    Egypt reveals heritage e-training portal    Three ancient rock-cut tombs discovered in Aswan    Sisi launches new support initiative for families of war, terrorism victims    Egypt expands e-ticketing to 110 heritage sites, adds self-service kiosks at Saqqara    Egypt's Irrigation Minister urges scientific cooperation to tackle water scarcity    Palm Hills Squash Open debuts with 48 international stars, $250,000 prize pool    Egypt's Democratic Generation Party Evaluates 84 Candidates Ahead of Parliamentary Vote    On Sport to broadcast Pan Arab Golf Championship for Juniors and Ladies in Egypt    Golf Festival in Cairo to mark Arab Golf Federation's 50th anniversary    Germany among EU's priciest labour markets – official data    Paris Olympic gold '24 medals hit record value    A minute of silence for Egyptian sports    Russia says it's in sync with US, China, Pakistan on Taliban    It's a bit frustrating to draw at home: Real Madrid keeper after Villarreal game    Shoukry reviews with Guterres Egypt's efforts to achieve SDGs, promote human rights    Sudan says countries must cooperate on vaccines    Johnson & Johnson: Second shot boosts antibodies and protection against COVID-19    Egypt to tax bloggers, YouTubers    Egypt's FM asserts importance of stability in Libya, holding elections as scheduled    We mustn't lose touch: Muller after Bayern win in Bundesliga    Egypt records 36 new deaths from Covid-19, highest since mid June    Egypt sells $3 bln US-dollar dominated eurobonds    Gamal Hanafy's ceramic exhibition at Gezira Arts Centre is a must go    Italian Institute Director Davide Scalmani presents activities of the Cairo Institute for ITALIANA.IT platform    







Thank you for reporting!
This image will be automatically disabled when it gets reported by several people.



Shedding light on optimal materials for harvesting sunlight underwater: Report
Published in Daily News Egypt on 19 - 03 - 2020

Research recently published by researchers from New York University in Joule found that scientists may have overlooked organic and inorganic materials that could be used to harness sunlight underwater and efficiently power autonomous submersible vehicles. The report 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.
“So far, the general trend has been to use traditional silicon cells, which we show are far from ideal once you go to a significant depth since silicon absorbs a large amount of red and infrared light, which is also absorbed by water–especially at large depths,” says Jason A. Röhr, a postdoctoral research associate and study's co-author. “With our guidelines, more optimal materials can be developed.”
Underwater vehicles, such as those used to explore the abyssal ocean, are currently limited by onshore power or inefficient on-board batteries, preventing travel over longer distances and periods of time. While solar technology takes off in land and in space, there is unchartered territory underwater, where submersibles have more freedom to roam. However, a unique challenge of submersible solar energy is that water scatters and absorbs much of the visible light spectrum, soaking up red solar wavelengths even at shallow depths before silicon-based solar cells would have a chance to capture them.
Most previous attempts to develop underwater solar cells have been constructed from silicon or amorphous silicon, each having narrow band gaps best suited for absorbing light on land. However, blue and yellow light manages to penetrate deep into the water column even as other wavelengths diminish, suggesting semiconductors with wider band gaps not found in traditional solar cells may provide a better fit for supplying energy underwater.
To better understand the potential of underwater solar cells, Röhr and colleagues assessed bodies of water ranging from the clearest regions of the Atlantic and Pacific oceans to a turbid Finnish lake, using a detailed-balance model to measure the limits of efficiency for solar cells at each location. Solar cells were shown to harvest energy from depths of 50 meters in Earth's clearest bodies of water, with chilly waters further boosting the cells' efficiency.
The researchers' calculations revealed that solar cell absorbers would function best with an optimum band gap of about 1.8 electronvolts at a depth of two meters and 2.4 electronvolts at a depth of 50 meters. These values remained consistent across all studied water sources, suggesting that solar cells could be tailored to specific operating depths rather than water locations.
Röhr noted that cheaply produced solar cells made from organic materials, which are known to perform well under low-light conditions, as well as alloys made with elements from groups three and five on the periodic table could be ideal in deep waters. Even though the substance of the semiconductors would differ from solar cells used on land, the overall design would remain relatively similar.
“While the sun-harvesting materials would have to change, the general design would not necessarily have to change all that much,” says Röhr. “Traditional silicon solar panels, like the ones you can find on your roof, are encapsulated to prohibit damage from the environment. Studies have shown that these panels can be immersed and operated in water for months without sustaining significant damage to the panels. Similar encapsulation methods could be employed for new solar panels made from optimal materials.” Now that they have uncovered what makes effective underwater solar cells tick, the researchers plan to begin developing optimal materials.
“This is where the fun begins!” says Röhr. “We have already investigated unencapsulated organic solar cells which are highly stable in water, but we still need to show that these cells can be made more efficient than traditional cells. Given how capable our colleagues around the world are, we are sure that we will see these new and exciting solar cells on the market in the near future.”


Clic here to read the story from its source.