Scientists at Berkeley Lab’s Molecular Foundry and colleagues have pioneered a new chemical mapping method that provides unprecedented insight into materials at the nanoscale. Moving beyond traditional static imaging techniques, which provide a snapshot in time, these new maps will guide researchers in deciphering molecular chemistry and interactions at the nanoscale—critical for artificial photosynthesis, biofuels production, and light-harvesting applications such as solar cells. “This new technique allows us to capture very high-resolution images of nanomaterials with a huge amount of physical and chemical information at each pixel,” said Dr. Alexander Weber-Bargioni, a postdoctoral scholar in the Imaging and Manipulation of Nanostructures Facility at the Foundry. “Usually when you take an image, you just get a picture of what this material looks like, but nothing more. With our method, we can now gain information about the functionality of a nanostructure with rich detail.” The Molecular Foundry is a U.S. Department of Energy (DOE) Office of Science nanoscience center and national user facility. With the Foundry’s state-of-the-art focused ion beam tool at its disposal, Dr. Weber-Bargioni and his team designed and fabricated a coaxial antenna capable of focusing light at the nanoscale, – a harnessing of light akin to wielding a sharp knife in a thunderstorm, Dr. Weber-Bargioni said. Consisting of gold wrapped around a silicon nitride atomic force microscope tip, this coaxial antenna serves as an optical probe for structures with nanometer resolution for several hours at a time. What’s more, unlike other scanning probe tips, it provides enough enhancement, or light intensity, to report the chemical fingerprint at each pixel while collecting an image (typically 256 pixels x 256 pixels).
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