▎ 摘　　要

We compare the electronic properties of graphene nanoribbons, with either bulk or edge substitutions, edge functionalization, or chemisorption. Chemical modifications can cause semiconductor-metal transitions, lifting of spin degeneracy, widening of bandgap, or appearance of non-dispersive impurity bands and doping. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim