Structural Evolution of Reduced Graphene Oxide of Varying Carbon sp(2) Fractions Investigated via Coulomb Blockade Transport

    Authors

    D. Joung;S. I. Khondaker

    Comments

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    Abbreviated Journal Title

    J. Phys. Chem. C

    Keywords

    ARRAYS; NANOPARTICLES; FILMS; DOTS; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, ; Multidisciplinary

    Abstract

    We investigate the structural evolution of reduced graphene oxide (RGO) sheets with carbon sp(2) fractions varying from 55 to 80% using low-temperature Coulomb blockade (CB) transport. At 4.2 K, all RGO sheets exhibit a complete suppression of current (CB) below a threshold voltage V-v the value of which decreased from 3.34 to 0.25 V with increasing carbon sp(2) fraction. From the temperature-dependent V-v we calculate an effective charging energy and individual graphene domain size of 160 meV and 1.34 nm at 55% carbon sp(2) fractions, respectively. These values are 20 meV and 4.18 nm at 80% carbon sp(2) fractions, respectively. This implies that with increasing reduction, newly formed sp(2) domains increase the effective size of the graphene domain. For an applied voltage V > V-v the current I follows a scaling law I similar to [(V - V-t)/V-t](alpha) where the scaling parameter alpha increases from 2.11 to 3.40 with increasing sp(2) fraction, suggesting that increasing sp(2) fraction creates more topological defects on the RGO. Our report provides a much desired insight into the structural evolution of RGO sheets.

    Journal Title

    Journal of Physical Chemistry C

    Volume

    117

    Issue/Number

    50

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    26776

    Last Page

    26782

    WOS Identifier

    WOS:000328920500043

    ISSN

    1932-7447

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