Fabrication and Characterisation of the First Graphene Ring Micro Electrodes (GRIMEs)

Abstract

We report the fabrication and characterisation of the first graphene ring micro electrodes, formed by dip coating fibre optics with subsequently reduced graphite oxide. The behaviour of the so-formed Graphene RIng Micro Electrodes (GRIMEs) is studied using the ferricyanide probe redox system while electrode thicknesses is assessed using established electrochemical methods. A ring electrode of ∼73 nm thickness is produced on 220 μm diameter fibre optics, corresponding to an inner to outer radius ratio of >0.999, so allowing for use of extant analytical descriptions of very thin ring micro electrodes in data analysis. GRIMEs are highly reliable (current response invariant over >3000 scans) with the microring design allowing for efficient use of electrochemically active graphene edge sites. Further, the associated nA scale currents neatly obviate issues relating to the high resistivity of undoped graphene. Thus, the use of graphene in ring micro electrodes improves the reliability of existing micro electrode designs and expands the range of use of graphene-based electrochemical devices.

Capillary-Force-Assisted Self-Assembly (CAS) of Highly Ordered and Anisotropic Graphene-Based Thin Films

“…For example, Eda et al prepared thin films of GO by slow vacuum filtration, which after reduction with hydrazine vapors yielded FOM values larger than 2 × 10 6 (calculated from the data in the graphs, Figure 3b of ref ), which is a few orders of magnitude larger than our CAS films. While it is difficult to compare the performance of CAS films made from rGO versus dip-coated films from GO with further reduction because of different processing conditions, the CAS films are slightly better than GO films prepared by dip-coating and subsequent chemical reduction with hydrazine for 20 h and thermal reduction at 700 °C, such as in Dickinson et al that yielded FOM of 3.6 × 10 3 .…”