Graphene Defect Image (2 of 2) (IMAGE) Northwestern University Caption This is an image of a hydroxylated defect site that allows for facile proton transfer through the pristine single-layer graphene substrate. Credit Credit: University of Minnesota Usage Restrictions Must include credit. Encouraged to use text of caption. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.