'Leaf-insired" wrinkles and twists 'may up solar panels' power output'

'Leaf-insired" wrinkles and twists 'may up solar panels' power output' Washington: Taking their cue from the humble leaf, researchers have used microscopic folds on the surface of photovoltaic material to considerably increase the power output of flexible, low-cost solar cells. But the folding technique increased absorption at this end of the spectrum by roughly 600 percent, the researchers found. "If you look at the solar spectrum, there is a lot of sunlight out there that we are wasting," Loo said. Although the math underlying the process is complex, the actual production is straightforward. Another advantage of the process is that it increases the durability of the solar panels by relieving mechanical stresses from bending. A standard plastic panel's energy production would be diminished by 70 percent after undergoing bending. Loo said the researchers drew their inspiration from leaves. So far, plastic panels have not been practical for widespread use because their energy production has been too low. If researchers can improve the plastic panels' efficiency, the material could produce power from a varied choice of surfaces from inserts in window panels to overlays on exterior walls or backpacks. "It is flexible, bendable, light weight and low cost," Loo said. In most cases, researchers have focused on increasing the efficiency of the plastic photovoltaic material itself. Loo said the folding method promises to increase those numbers. "This is a very simple process that you can use with any material," she said. By controlling how fast different sections of the adhesive cured, the team was able to introduce stresses in the material and generate ripples in the surface. The team found that a surface containing a mix of wrinkles and folds produced first class results. "This is a way to increase efficiency. The research team created the folded surface in Howard Stone's laboratory in the mechanical and aerospace engineering department by carefully curing a layer of liquid photographic adhesive with ultraviolet light. "By adding these curves, we create a type of wave guide. "However, when I actually constructed solar cells on top of the folded surface, its effect was better than my expectations. " . The research team's work involves photovoltaic systems made of relatively cheap plastic. Recent developments have been promising: a team from UCLA recently announced a system with a 10. "We have tested it with other polymers and it works as well. Jong Bok Kim, a postdoctoral researcher in chemical and biological engineering and the paper's lead author, explained that the folds on the surface of the panels channel light waves through the material in much the same way that canals guide water through farmland. By curving the light through the material, the researchers essentially trap the light inside the photovoltaic material for a longer time, which leads to greater absorption of light and generation of energy. "I expected that it would increase the photocurrent because the folded surface is quite similar to the morphology of leaves, a natural system with high light harvesting efficiency," said Kim, a postdoctoral researcher in chemical and biological engineering. The study has been published in the journal Nature Photonics . 'Leaf-insired" wrinkles and twists 'may up solar panels' power output' Trade News selected by Local Linkup on 01/05/2012