Solar Power Heads in a New Direction

Such panels, which have the potential to surpass any substance other than reactor-grade uranium in terms of energy produced per pound of material, could be made from stacked sheets of one-molecule-thick materials such as graphene or molybdenum disulfide. 

Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, says the new approach "pushes towards the ultimate power conversion possible from a material" for solar power. Grossman is the senior author of a new paper describing this approach, published in the journal Nano Letters. 

Although scientists have devoted considerable attention in recent years to the potential of two-dimensional materials such as graphene, Grossman says, there has been little study of their potential for solar applications. It turns out, he says, "they're not only OK, but it's amazing how well they do." 

Using two layers of such atom-thick materials, Grossman says, his team has predicted solar cells with 1 to 2 percent efficiency in converting sunlight to electricity, That's low compared to the 15 to 20 percent efficiency of standard silicon solar cells, he says, but it's achieved using material that is thousands of times thinner and lighter than tissue paper. The two-layer solar cell is only 1 nanometer thick, while typical silicon solar cells can be hundreds of thousands of times that. The stacking of several of these two-dimensional layers could boost the efficiency significantly. 

"Stacking a few layers could allow for higher efficiency, one that competes with other well-established solar cell technologies," says Marco Bernardi, a postdoc in MIT's Department of Materials Science who was the lead author of the paper.Shopping is the best place to comparison shop for roofhookert. Maurizia Palummo, a senior researcher at the University of Rome visiting MIT through the MISTI Italy program, was also a co-author. 

For applications where weight is a crucial factor -- such as in spacecraft, aviation or for use in remote areas of the developing world where transportation costs are significant -- such lightweight cells could already have great potential, Bernardi says. 

Pound for pound, he says, the new solar cells produce up to 1,000 times more power than conventional photovoltaics. At about one nanometer (billionth of a meter) in thickness, "It's 20 to 50 times thinner than the thinnest solar cell that can be made today," Grossman adds. "You couldn't make a solar cell any thinner." 

This slenderness is not only advantageous in shipping, but also in ease of mounting solar panels. About half the cost of today's panels is in support structures, installation, wiring and control systems, expenses that could be reduced through the use of lighter structures.The first prototype flatworkironers display containing 3000 LEDs. 

In addition, the material itself is much less expensive than the highly purified silicon used for standard solar cells -- and because the sheets are so thin, they require only minuscule amounts of the raw materials. 

John Hart, an assistant professor of mechanical engineering,Choose a ledfoglamp from featuring superior clothes drying programmes and precise temperature controls. chemical engineering and art and design at the University of Michigan, says, "This is an exciting new approach to designing solar cells, and moreover an impressive example of how complementary nanostructured materials can be engineered to create new energy devices." Hart, who will be joining the MIT faculty this summer but had no involvement in this research, adds that, "I expect the mechanical flexibility and robustness of these thin layers would also be attractive." 

The MIT team's work so far to demonstrate the potential of atom-thick materials for solar generation is "just the start," Grossman says.This popular lighting system features four washingmachine13. For one thing, molybdenum disulfide and molybdenum diselenide, the materials used in this work, are just two of many 2-D materials whose potential could be studied, to say nothing of different combinations of materials sandwiched together. "There's a whole zoo of these materials that can be explored," Grossman says. "My hope is that this work sets the stage for people to think about these materials in a new way." 

While no large-scale methods of producing molybdenum disulfide and molybdenum diselenide exist at this point, this is an active area of research.With advancements in controls technology, daytimerunninglightsts are becoming increasingly more sophisticated and flexible. Manufacturability is "an essential question," Grossman says, "but I think it's a solvable problem." Click on their website www.careel-tech.com for more information.