AsianScientist (Aug. 11, 2015) – Graphene has been called the miracle material but the single-atomic layer material is still seeking its place in the materials world. Now a method to make ‘defective’ graphene could provide the answer.
In a study published in Nanotechnology, a team of researchers report that they have developed a simple electrochemical approach which allows defects to intentionally be created in the graphene, altering its electrical and mechanical properties and making the material even more useful.
The researchers used a technique called electrochemical synthesis to break graphite flakes into graphene layers. By varying the voltage they could change the resulting graphene’s thickness, flake area, and number of defects—all of which alter the properties of graphene.
“Graphene is basically a metal—so it’s somewhat boring!” explains Professor Mario Hofmann from the National Cheng Kung University in Taiwan. “But when you start adding defects you begin to get interesting effects.”
Although graphene research has attracted a lot of attention—particularly after winning the Physics Nobel in 2010—it is graphene’s ‘defective’ counterpart graphene oxide that could be first to carve out a significant market share as polymer fillers and battery electrodes. More precise control over the amount and nature of defects could bring about new applications of graphene in drug delivery or electronics.
“Whilst electrochemistry has been around for a long time it is a powerful tool for nanotechnology because it’s so finely tuneable.” continues Hofmann. “In graphene production we can really take advantage of this control to produce defects.”
Hofmann’s team developed a system of pulsed instead of continuous voltages, allowing them to unravel the exfoliation mechanism. To monitor the evolution of the graphene in the solvent they found that simply tracking the solution’s transparency could give them quantitative information on the efficiency and onset of exfoliation.
They next plan to study the effects of adjusting the pulse durations throughout the exfoliation process to improve the amount of exfoliated graphene and introduce more complex pulse shapes to selectively produce certain types of graphene defects.
The article can be found at: Hofmann et al. (2015) Controlling the Properties of Graphene Produced by Electrochemical Exfoliation.
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Source: IOP Publishing; Photo: Shutterstock.
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