title: Basal-Plane Functionalization of Chemically Exfoliated Molybdenum Disulfide by Diazonium Salts.
abstract: Although transition metal dichalcogenides such as MoS2 have been recognized as highly potent two-dimensional nanomaterials, general methods to chemically functionalize them are scarce. Herein, we demonstrate a functionalization route that results in organic groups bonded to the MoS2 surface via covalent C-S bonds. This is based on lithium intercalation, chemical exfoliation and subsequent quenching of the negative charges residing on the MoS2 by electrophiles such as diazonium salts. Typical degrees of functionalization are 10-20 atom % and are potentially tunable by the choice of intercalation conditions. Significantly, no further defects are introduced, and annealing at 350 °C restores the pristine 2H-MoS2. We show that, unlike both chemically exfoliated and pristine MoS2, the functionalized MoS2 is very well dispersible in anisole, confirming a significant modification of the surface properties by functionalization. DFT calculations show that the grafting of the functional group to the sulfur atoms of (charged) MoS2 is energetically favorable and that S-C bonds are formed.
authors.affiliation: †Chair of Organic Chemistry II and Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestraße 42, 91054 Erlangen, Germany.
authors.forename: Kathrin C
authors.initials: KC
authors.lastname: Knirsch
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|§School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Nina C
authors.initials: NC
authors.lastname: Berner
authors.affiliation: §School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Hannah C
authors.initials: HC
authors.lastname: Nerl
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Clotilde S
authors.initials: CS
authors.lastname: Cucinotta
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Gholamvand
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|§School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Niall
authors.initials: N
authors.lastname: McEvoy
authors.affiliation: #Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: †Chair of Organic Chemistry II and Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestraße 42, 91054 Erlangen, Germany.
authors.forename: Irena
authors.initials: I
authors.lastname: Abramovic
authors.affiliation: †Chair of Organic Chemistry II and Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestraße 42, 91054 Erlangen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Vecera
authors.forename: Marcus
authors.initials: M
authors.lastname: Halik
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Stefano
authors.initials: S
authors.lastname: Sanvito
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|§School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Georg S
authors.initials: GS
authors.lastname: Duesberg
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|§School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Valeria
authors.initials: V
authors.lastname: Nicolosi
authors.affiliation: †Chair of Organic Chemistry II and Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestraße 42, 91054 Erlangen, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Hauke
authors.affiliation: †Chair of Organic Chemistry II and Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestraße 42, 91054 Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hirsch
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Coleman
authors.affiliation: ‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.|∥School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Claudia
authors.initials: C
authors.lastname: Backes
keywords: 1T-polytype; basal-plane; chemical exfoliation; covalent functionalization; layered materials; molybdenum disulfide; transition metal dichalcogenides