Researchers from Skoltech and other institutions have uncovered the optimal conditions for storing graphene oxide, a promising material with diverse applications. Their findings shed light on the complex behavior of this material and pave the way for better preservation and utilization.
Unveiling the Enigma of Graphene Oxide
Graphene oxide as a versatile and promising material useful in electronics, energy storage and many other fields has been recognized. Instead, the main barrier stem from an odd challenge: properties of the material can change over time, which leads to variation and inconsistency in performance.
A team of researchers headed by Skoltech scientists and the Emanuel Institute of Biochemical Physics has shed light on the cold-induced switch registered in a list of experiments with healthy volunteers. Through a systematic study, they showed that the preservation of graphene oxide very much depends on its storage conditions.
The researchers prepared multiple identical samples of graphene oxide with the same chemical makeup and preparation. They then stored these samples under a variety of conditions — from room temperature to refrigeration and with or without light. The team tracked the properties of the samples that changed over 150 or so days absorption spectra, X-ray photoelectron radiation spectra, hydrogen index and viscosity of suspensions.
The Optimal Storage Conditions Revealed
The results were unmistakable: this is to be stored cold and no light should reach the graphene oxide.
Graphene oxide samples stored at room temperature and in light undergo a process known as ‘reduction’ – removal of oxygen-containing groups from the surface of the material. But this process switched the material back into plain graphene, stripping it of its special attributes.
In contrast, exposure to a cold, dark environment had no effect on the graphene oxide samples. The oxygen-containing groups were still there and the material retained all of its known properties.
The researchers went on to examine the mechanisms that drive these activities and used supercomputer atomistic modeling to study them further. Given the results of their quantum chemical calculations, such oxygen groups on the surface of graphene oxide are unlikely to be uniformly spread out as traditionally believed and have a preference for clustering within specific regions in its most stable state. That concentration oxygen groups can affect the optical spectra of material and create regions where only graphene is present, where oxygen is partially “migrated” out.
Conclusion
The results of this research could pave the way for more effective storage and management of graphene oxide, a promising material impacting multiple sectors. Our results should motivate the research community to etch or dope GO electronics at low temperatures, so that the structural integrity of GO remains high, and enable consistent performances for its many devices. Understanding this will allow applications of graphene oxide to be developed and more widely-utilised, which in turn will help with advances in devices such as electronics and energy storage.
