Figure . Scheme of the atomic structure and density of states for pristine (left) and intercalated (right) 2D COFs. Atomic structures for pristine and intercalated 2D COFs are shown in "perspective" and "top" views for each structure. The DOS illustration shows how TM intercalation promotes carbon p-orbital and transition metal d-orbital interactions, potentially reducing the bandgap from insulating to semiconducting. For visualization aid, DOS projections are not to scale. Oxygen projection is not plotted since oxygen orbitals generally do not show important contributions to the DOS near the Fermi energy for these particular structures. Atom colors in the structures correspond to the colors shown in the DOS projections.