A study led by UChicago researchers, published Sept.
Stacking thin layers of materials offers a range of possibilities for making electronic devices with unique properties. But manufacturing such films is a delicate process, with little room for error.
"The scale of the problem we're looking at is, imagine trying to lay down a flat sheet of plastic wrap the size of Chicago without getting any air bubbles in it," said Jiwoong Park, a UChicago professor with the Department of Chemistry, the Institute for Molecular Engineering and the James Franck Institute, who led the study. "When the material itself is just atoms thick, every little stray atom is a problem."
Today, these layers are "grown" instead of stacking them on top of one another. But that means the bottom layers have to be subjected to harsh growth conditions such as high temperatures while the new ones are added—a process that limits the materials with which to make them.
Park's team instead made the films individually. Then they put them into a vacuum, peeled them off and stuck them to one another, like Post-It notes. This allowed the scientists to make films that were connected with weak bonds instead of stronger covalent bonds—interfering less with the perfect surfaces between the layers.
Read more at: https://phys.org/news/2017-09-scientists-atoms-thick-post-it-solar-cells.html#jCp
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