Contactless Surface Conductivity
Mapping of Graphene
Oxide Thin Films Deposited on Glass with Scanning Electrochemical
Microscopy
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Abstract
The present article introduces a rapid, very sensitive,
contactless
method to measure the local surface conductivity with Scanning Electrochemical
Microscopy (SECM) and obtain conductivity maps of heterogeneous substrates.
It is demonstrated through the study of Graphene Oxide (GO) thin films
deposited on glass. The adopted substrate preparation method leads
to conductivity disparities randomly distributed over approximately
100 μm large zones. Data interpretation is based on an equation
system with the dimensionless conductivity as the only unknown parameter.
A detailed prospection provides a consistent theoretical framework
for the reliable quantification of the conductivity of GO with SECM.
Finally, an analytical approximation of the conductivity as a function
of the feedback current is proposed, making any further interpretation
procedure straightforward, as it does not require iterative numerical
simulations any more. The present work thus provides not only valuable
information on the kinetics of GO reduction in mild conditions but
also a general and simplified interpretation framework that can be
extended to the quantitative conductivity mapping of other types of
substrates