Researchers at the U.S. Department of Energy’s Los Alamos National Laboratory have developed and tested an atomically thin graphene coating for photocathodes – materials that can convert photons to free electrons, which are used to create electron beams. Photocathodes need to have a protective coating because the chemical reaction from photons striking the photocathodes to emit electrons also produces a corrosive gas that can quickly degrade the photocathodes. Graphene possesses high gas impermeability, yet electrons can still pass through it.
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