title: Covalent functionalization of monolayered transition metal dichalcogenides by phase engineering.
abstract: Chemical functionalization of low-dimensional materials such as nanotubes, nanowires and graphene leads to profound changes in their properties and is essential for solubilizing them in common solvents. Covalent attachment of functional groups is generally achieved at defect sites, which facilitate electron transfer. Here, we describe a simple and general method for covalent functionalization of two-dimensional transition metal dichalcogenide nanosheets (MoS₂, WS₂ and MoSe₂), which does not rely on defect engineering. The functionalization reaction is instead facilitated by electron transfer between the electron-rich metallic 1T phase and an organohalide reactant, resulting in functional groups that are covalently attached to the chalcogen atoms of the transition metal dichalcogenide. The attachment of functional groups leads to dramatic changes in the optoelectronic properties of the material. For example, we show that it renders the metallic 1T phase semiconducting, and gives it strong and tunable photoluminescence and gate modulation in field-effect transistors.
authors.affiliation: Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, USA.
authors.forename: Damien
authors.initials: D
authors.lastname: Voiry
authors.affiliation: 1] Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, USA [2] Department of Chemical and Biochemical Engineering, Rutgers University, 98 Brett Road, Piscataway, New Jersey 08854, USA.
authors.forename: Anandarup
authors.initials: A
authors.lastname: Goswami
authors.affiliation: Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, USA.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kappera
authors.affiliation: Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, USA.
authors.forename: Cecilia de Carvalho Castro
authors.initials: Cde C
authors.lastname: e Silva
authors.affiliation: US Army RDECOM-ARDEC, Acoustics and Networked Sensors Division, Picatinny Arsenal, New Jersey 07806, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kaplan
authors.affiliation: 1] WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan [2] JST, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Takeshi
authors.identifier: 0000000223180433
authors.initials: T
authors.lastname: Fujita
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen
authors.affiliation: 1] Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, USA [2] Department of Chemical and Biochemical Engineering, Rutgers University, 98 Brett Road, Piscataway, New Jersey 08854, USA.
authors.forename: Tewodros
authors.initials: T
authors.lastname: Asefa
authors.affiliation: Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, USA.
authors.forename: Manish
authors.initials: M
authors.lastname: Chhowalla