The limitations of conventional and current solar cells include high production cost, low operating efficiency and durability, and many cells rely on toxic and scarce materials. Northwestern University researchers have developed a new solar cell that, in principle, will minimize all of these solar energy technology limitations.
In particular, the device is the first to solve the problem of the Grtzel cell, a promising low-cost and environmentally friendly solar cell with a significant disadvantage: it leaks. The dye-sensitized cell's electrolyte is made of an organic liquid, which can leak and corrode the solar cell itself.
Grtzel cells use a molecular dye to absorb sunlight and convert it to electricity, much like chlorophyll in plants. But the cells typically don't last more than 18 months, making them commercially unviable. Researchers have been searching for an alternative for two decades.
At Northwestern, where interdisciplinary collaboration is a cornerstone, nanotechnology expert Robert P. H. Chang challenged chemist Mercouri Kanatzidis with the problem of the Grtzel cell. Kanatzidis' solution was a. Thus, the new all solid-state solar cell is inherently stable.
"The Grtzel cell is like having the concept for the light bulb but not having the tungsten wire or carbon material," said Kanatzidis, of the need to replace the troublesome liquid. "We created a robust novel material that makes the Grtzel cell concept work better. Our material is solid, not liquid, so it should not leak or corrode."
Postdoctoral fellow In Chung in the Kanatzidis group worked closely with graduate student Byunghong Lee in the Chang group to develop the new cells, achieving performance gains that amounted to approximately 1 percent per month.
In the Northwestern cell, a thin-film compound made up of cesium, tin and iodine, called CsSnI3, replaces the entire liquid electrolyte of the Grtzel cell. Details of the new solar cell --
|Contact: Megan Fellman|