Luo, ZhengtangVora, PatrickMele, Eugene JJohnson, A.T. CharlieKikkawa, James M2023-05-232023-05-232009-03-192011-01-06https://repository.upenn.edu/handle/20.500.14332/43381We report broadband visible photoluminescence from solid graphene oxide, and modifications of the emission spectrum by progressive chemical reduction. The data suggest a gapping of the two-dimensional electronic system by removal of π-electrons. We discuss possible gapping mechanisms, and propose that a Kekule pattern of bond distortions may account for the observed behavior.Physical Sciences and MathematicsPhysicsArticle