Browsing by Author "Wei, Y"

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    Precise tuning chemistry and tailoring defects of graphene oxide films by low energy ion beam irradiation
    (Elsevier, 2020-03-01) Wei, Y; Pastuovic, Z; Murphy, T; Gore, DB
    Precise tuning chemistry and tailoring nanopores of graphene oxide (GO) thin films are vital for their application for liquid and gas separation. In this work, ultra-thin GO films with thicknesses of about 150 nm were prepared and then modified by a low energy carbon ion beam with ion fluences ranging from 1 × 1015 ions·cm−2 to 1 × 1017 ions·cm−2. An ion fluence of 1 × 1016 ions·cm−2 is a threshold for the changes to the surface geometry (i.e. the chemical state and the consequent morphology) of the GO films. Moreover, X-ray photoelectron spectroscopy (XPS) reveals that oxygen loss in ion beam-induced reduction of GO films was mainly by the elimination of the unstable C[dbnd]O species. Raman spectroscopy indicates that a mass of defects with a mean defect distance of about 1.4 nm was generated in GO films by C+ irradiation. According to SRIM simulation, an average of 208 carbon vacancies were created in the GO film per impinging C+. These results suggest that low energy carbon ion beam irradiation is promising for simultaneously reducing and drilling nanoscale pores on GO surfaces in a controllable manner, which could be used for engineering GO-based separation membranes. © 2019 Published by Elsevier B.V.