Fluorine absorption on single and bilayer graphene: Role of sublattice   and layer decoupling
  The fluorination of mono- and bi-layer graphene have been studied by means of ab-initio DFT calculations. The stability of CF$_x$ systems are found to depend on both the F coverage and on the position of the F atoms regarding the C sublattices. When F atoms is chemisorbed to C atoms belonging to the same sublattice, low coverage is preferred. Otherwise, large F coverable is more stable (up to C$_4$F). The difference of charge distribution between the two carbon sublattices explains this finding that is confirmed by the analysis of the diffusion barriers. Binding energy of F on bi-layer systems is also computed slightly smaller than on monolayer and electronic decoupling is observed when only one of the layer is exposed to fluorine. 
Hern\'an Santos and Luc Henrard
cond-mat.mtrl-sci