title: Covalent Carbene Functionalization of Graphene: Toward Chemical Band-Gap Manipulation.
abstract: In this work, we employ dibromocarbene (DBC) radicals to covalently functionalize solution exfoliated graphene via the formation of dibromocyclopropyl adducts. This is achieved using a basic aqueous/organic biphasic reaction mixture to decompose the DBC precursor, bromoform, in conjunction with a phase-transfer catalyst to facilitate ylide formation and carbene migration to graphene substrates. DBC-functionalized graphene (DBC-graphene) was characterized using a range of spectroscopic and analytical techniques to confirm the covalent nature of functionalization. Modified optical and electronic properties of DBC-graphene were investigated using UV-vis spectroscopy, analysis of electrical I-V transport properties, and noncontact terahertz time-domain spectroscopy. The implications of carbene functionalization of graphene are considered in the context of scalable radical functionalization methodologies for bulk-scale graphene processing and controlled band-gap manipulation of graphene.
authors.affiliation: National Physical Laboratory , Teddington, London TW11 0LW, United Kingdom.
authors.forename: Toby
authors.initials: T
authors.lastname: Sainsbury
authors.affiliation: National Physical Laboratory , Teddington, London TW11 0LW, United Kingdom.
authors.forename: Melissa
authors.initials: M
authors.lastname: Passarelli
authors.affiliation: National Physical Laboratory , Teddington, London TW11 0LW, United Kingdom.
authors.forename: Mira
authors.initials: M
authors.lastname: Naftaly
authors.affiliation: National Physical Laboratory , Teddington, London TW11 0LW, United Kingdom.
authors.forename: Sam
authors.initials: S
authors.lastname: Gnaniah
authors.affiliation: National Physical Laboratory , Teddington, London TW11 0LW, United Kingdom.
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Spencer
authors.affiliation: National Physical Laboratory , Teddington, London TW11 0LW, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
keywords: band gap; carbene; dibromocarbene; functionalization; graphene