Jung et al. found that iodine anions (I3 and I5)adsorbed on single layer graphene presented strong Ramanscattering, and the Raman signals of an intercalated bromine(Br2) layer showed the same characteristics.79 As shown inFig. 4A, the increase of graphene layers induced the significantdecrease of Raman signal intensities of iodine anions (I3 and I5),and the intensities were 30 times stronger on one layer of graphenethan bulk graphite. A similar phenomenon illustrated in Fig. 4B wasdemonstrated in which the single layer intercalated bromine (Br2)Raman intensity in bulk graphite was 6 times bigger than in fourlayers of graphene.