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.

Janus graphene from asymmetric two-dimensional chemistry

“…Figure 2a demonstrates the evolution of Raman spectrum in the fabrication process of Janus graphene. Single-sided photochlorination of individually exfoliated monolayer graphene was first carried out on 300 nm SiO 2 /Si, following the procedures described by our group previously 21 . Chlorine molecules were introduced to our home-made quartz reaction vessel by air-flow carrying a chlorine/ nitrogen mixture under 1 atm of pressure.…”

“…The as-grown graphene films are predominately monolayer, with a small percentage (less than B5%) of the area having few layers, owing to the self-limiting effect of copper surface under low growth pressure. To avoid the precontamination of Cl species, the CVD-grown graphene was detached by etching the copper away with 2.0 M Fe 2 (SO4) 3 aqueous solution rather than FeCl 3 as our previous work reported 21 . Functionalisation of graphene.…”

“…Functionalisation of graphene. Photochlorination of graphene was conducted in a home-made gas-phase reaction system following the procedures our group developed previously 21 . Chlorine gas was obtained by adding 15 ml hydrochloric acid 9 M slowly into 5 g MnO 2 at 60 o C and dried by concentrated sulphuric acid before entering the photoreactor (6 Â 3 Â 2.5 cm 3 ; transmittance is 485% in the UV zone).…”

Sensing at the Surface of Graphene Field‐Effect Transistors

“…[12] The broad sensing potential of graphene can only be unlocked by the introduction of sensitizer (bio)molecules and structures, e.g. various inorganic groups, [23][24][25][81][82][83][84][85][86][87][88][89][90] organic or organometallic molecules, [37,[91][92][93][94][95][96] DNAs, [97][98][99][100][101] proteins, [102] peptides, [30,31,103,104] nanoparticles, [105,106,107] and 2D heterostructure. [51,52,61,108] These molecules are able to respond chemically or physically to their nearby environment, whose responses could then be transduced into an appreciable change in the conductivity of the carbon-based honeycomb scaffold.…”

Structure of graphene and its disorders: a review

“…Figure 14(d) shows the sp 3 defects produced by the chlorination of graphene following the method described in a previous study [223]. Cl atoms were connected to the graphene sheets via covalent bonds (Cl–C) after a five-minute reaction.…”