Microscopic mechanisms of graphene electrolytic delamination from metal substrates

In this paper, hydrogen bubbling delamination of graphene (Gr) from copper using a strong electrolyte (KOH) water solution was performed, focusing on the effect of the KOH concentration (CKOH) on the Gr delamination rate. A factor of ∼10 decrease in the time required for the complete Gr delamination...

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Bibliographic Details
Published in:Applied physics letters 2014-06, Vol.104 (23)
Main Authors: Fisichella, G., Di Franco, S., Roccaforte, F., Ravesi, S., Giannazzo, F.
Format: Article
Language:English
Subjects:
Applied physics
AQUEOUS SOLUTIONS
ATOMIC FORCE MICROSCOPY
Bubbling
CATHODES
COMPRESSION
COPPER
Delamination
Dependence
ELECTROLYTES
GRAPHENE
HYDROGEN
Mathematical morphology
MEMBRANES
NANOSCIENCE AND NANOTECHNOLOGY
NUCLEATION
POTASSIUM HYDROXIDES
Silicon dioxide
SILICON OXIDES
SUBSTRATES
SUPERSATURATION
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Summary:In this paper, hydrogen bubbling delamination of graphene (Gr) from copper using a strong electrolyte (KOH) water solution was performed, focusing on the effect of the KOH concentration (CKOH) on the Gr delamination rate. A factor of ∼10 decrease in the time required for the complete Gr delamination from Cu cathodes with the same geometry was found increasing CKOH from ∼0.05 M to ∼0.60 M. After transfer of the separated Gr membranes to SiO2 substrates by a highly reproducible thermo-compression printing method, an accurate atomic force microscopy investigation of the changes in Gr morphology as a function of CKOH was performed. Supported by these analyses, a microscopic model of the delamination process has been proposed, where a key role is played by graphene wrinkles acting as nucleation sites for H2 bubbles at the cathode perimeter. With this approach, the H2 supersaturation generated at the electrode for different electrolyte concentrations was estimated and the inverse dependence of td on CKOH was quantitatively explained. Although developed in the case of Cu, this analysis is generally valid and can be applied to describe the electrolytic delamination of graphene from several metal substrates.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4882165