title: Photochemical chlorination of graphene.
abstract: We report the covalent functionalization of graphene by photochemical chlorination. The gas-phase photochlorination of graphene, followed by the structural transformation of the C-C bonds from sp(2) to sp(3) configuration, could remove the conducting π-bands and open up a band gap in graphene. X-ray photoelectron spectroscopy revealed that chlorine is grafted to the basal plane of graphene, with about 8 atom % chlorine coverage. Raman spectroscopy, atomic force microscopy, and transmission electron microscopy all indicated that the photochlorinated graphene is homogeneous and nondestructive. The resistance increases over 4 orders of magnitude and a band gap appears upon photochlorination, confirmed by electrical measurements. Moreover, localized photochlorination of graphene can facilitate chemical patterning, which may offer a feasible approach to the realization of all-graphene circuits.
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Zhou
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Hailin
authors.initials: H
authors.lastname: Peng
authors.forename: Kai
authors.initials: K
authors.lastname: Yan
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Zhongfan
authors.initials: Z
authors.lastname: Liu