Graphene performance can be doubled by eliminating silicon contamination, study finds

According to a new study by scientists at the RMIT University in Australia, the performance of "supermaterial" graphene in electronics can be almost doubled by eliminating silicon contamination.

Graphene is a carbon allotrope, consisting of a network of carbon atoms of a thickness of one atom. He is known for some unusual properties. It is an electrically conductive, super-capacitive, biodegradable and transparent material that can take almost any form. Graphene is ultra-lightweight but 200 times stronger than steel. It can drive electricity 10 times better than copper.

Graphene is considered a transformative material for flexible electronics. It can help create unbreakable phone screens, flexible computers, powerful chips, bio-sensors, new supercomputers and even space elevators.

But, despite its many properties, graphene has not, so far, been up to its potential.

Now a group of scientists, led by Drs. Dorna Esrafilzadeh and Rouhollah Ali Jalili of RMIT University, said they have finally found the reason for the disappointing performance of graphene. In their study, these scientists describe a new approach that can help the industry produce better graphene.

The scientists collected commercially available graphene samples and examined them with the help of a powerful transient scanning electron microscope. They found that these samples were contaminated with high levels of silicon. The silicon contained in graphene comes from natural graphite, used as raw material for the production of graphene. During the treatment of the graphite, silicon impurities remain in the samples, which ultimately affects the performance of graphene.

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

When researchers used contaminated graphene as an electrode in their tests, it was found that the performance of the latter was up to 50% worse.

"This level of inconsistency may have blocked the emergence of major industry applications for graphene-based systems," Esrafilzadeh added.

The researchers also revealed that graphene became vulnerable to surface contamination because of its two-dimensional (2D) structure.

When they used pure graphene samples (without any silicon contamination) to build a supercapacitor, their performance was exceptionally good and demonstrated the greatest electrical charge load capacity for a graphene sample up to ## EQU1 ## 39, now.

A pure graphene sample was also used to create a moisture sensor, and it also presented the highest level of sensitivity.

"We hope this research will help unlock the exciting potential of these materials."

The results of the study are published in a journal Nature Communications.