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Scientists have removed the contamination of silicon from graphene to double its performance



November 29, 2018

(Nanowerk News) New research reveals why graphene did not change electronics by promises and shows how to double its performance and ultimately exploit its extraordinary potential.

Grafen is the most powerful material ever tested. It's also flexible, transparent and ten times better than copper.

After Grafen's research was awarded the Nobel Prize for Physics in 2010, it was awarded as a transformation material for flexible electronics, more powerful computer chips and solar panels, water filters and biosensors. But performance was mixed and adopting in the industry slowly.

A study has now been published Natural communication ("Silicone as the ubiquitous contaminant in graphene derivatives with a significant effect on equipment performance") identifies silicon contamination as the main cause of unsatisfactory results and details of how to produce high performance, pure graphene.

RMIT University Team led by Dr. Dorna Esrafilzadeh and Dr. Rouhollah Ali Jalili has examined commercial graphene specimens of the atom by an atom with a state-of-the-art transient electron microscope.

"We have found high levels of silicon contamination in commercially available graphene, with a major impact on the performance of the material," Esrafilzadeh said.

The test showed that silicon present in natural graphite, a raw material used to produce graphene, was not completely removed after processing.

"We believe that this contamination is at the heart of many seemingly inconsistent reports of the properties of graphene and perhaps many other atom-thin two-dimensional (2D) materials," Esrafilzadeh said.

"Grafen has been billed as a transformation, but has not yet achieved a significant commercial impact, as well as some similar 2D nanomaterials, and we now know why it does not meet the promise and what needs to be done to exploit its full potential."

Testing determined not only these impurities but also showed that they have a great effect on performance, while the contaminated material acts up to 50% worse in tests like electrodes.

"This degree of discrepancy can cause major industrial applications in graphene-based systems, but it also prevents the development of regulatory frameworks that govern the deployment of such layered nanomaterials that are designed to become the backbone of new generation devices," she said.

The two-dimensional property of graphite foils, which is only one thick atom, is ideal for electricity storage and new sensor technologies that rely on a high surface area.

This study reveals that the property of 2D is also an Achilles heel, which is so vulnerable to surface contamination, and emphasizes how important high-purity graphite is to produce cleaner graphene.

The use of pure graphene has shown that the researchers have shown how the material was used extremely well when a supercapacitor, a super battery, was built.

During testing, the ability of the device to maintain the electrical charge was massive. In fact, it was the largest capacity so far recorded for graphene and considering the assumed theoretical capacity of the material.

In collaboration with the Center for Advanced Materials and Industrial Chemistry, the RMIT team then used a clean graph to create the versatile humidity sensor with the highest sensitivity and the lowest detection limit ever recorded.

These findings represent a milestone for a complete understanding of atom-thin two-dimensional materials and their successful integration into high-performance commercial devices.
"We hope this research will help unleash the exciting potential of these materials."


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