Chemical Bonding of Partially Fluorinated Graphene

Understanding the interactions of graphene and chemical additives is crucial to achieve control over chemically modified graphene materials. Here, density functional theory and experiments are used to elucidate the chemical bonding of partially fluorinated graphene. This material includes F–C bonds whose ionicity varies depending upon local concentration and structure. Three bonding states dominate. Single fluorine on graphene forms a semi-ionic bond with a C atom in an sp2 configuration. Fluorine in highly stable domains of poly(carbon fluoride) consists of covalent F–C bonds alternating in ortho position one to another on both sides of graphene. Fluorine in regions of poly(tetracarbon fluoride) has F species on one side of graphene in para position one to another, and F–C bonds with a character intermediate between the semi-ionic and covalent. Such variability in chemical bonding could be exploited to tailor fluorinated graphene materials to achieve a variety of properties.