Tag Archives: indium

Substituting graphene and other carbon materials for scarce metals

A Sept. 19, 2017 news item on Nanowerk announces a new paper from the Chalmers University of Technology (Sweden), the lead institution for the Graphene Flagship (a 1B Euro 10 year European Commission programme), Note: A link has been removed,

Scarce metals are found in a wide range of everyday objects around us. They are complicated to extract, difficult to recycle and so rare that several of them have become “conflict minerals” which can promote conflicts and oppression. A survey at Chalmers University of Technology now shows that there are potential technology-based solutions that can replace many of the metals with carbon nanomaterials, such as graphene (Journal of Cleaner Production, “Carbon nanomaterials as potential substitutes for scarce metals”).

They can be found in your computer, in your mobile phone, in almost all other electronic equipment and in many of the plastics around you. Society is highly dependent on scarce metals, and this dependence has many disadvantages.

A Sept. 19, 2017 Chalmers University of Technology press release by Ulrika Ernstrom,, which originated the news item, provides more detail about the possibilities,

They can be found in your computer, in your mobile phone, in many of the plastics around you and in almost all electronic equipment. Society is highly dependent on scarce metals, and this dependence has many disadvantages.
Scarce metals such as tin, silver, tungsten and indium are both rare and difficult to extract since the workable concentrations are very small. This ensures the metals are highly sought after – and their extraction is a breeding ground for conflicts, such as in the Democratic Republic of the Congo where they fund armed conflicts.
In addition, they are difficult to recycle profitably since they are often present in small quantities in various components such as electronics.
Rickard Arvidsson and Björn Sandén, researchers in environmental systems analysis at Chalmers University of Technology, have now examined an alternative solution: substituting carbon nanomaterials for the scarce metals. These substances – the best known of which is graphene – are strong materials with good conductivity, like scarce metals.
“Now technology development has allowed us to make greater use of the common element carbon,” says Sandén. “Today there are many new carbon nanomaterials with similar properties to metals. It’s a welcome new track, and it’s important to invest in both the recycling and substitution of scarce metalsfrom now on.”
The Chalmers researchers have studied  the main applications of 14 different metals, and by reviewing patents and scientific literature have investigated the potential for replacing them by carbon nanomaterials. The results provide a unique overview of research and technology development in the field.
According to Arvidsson and Sandén the summary shows that a shift away from the use of scarce metals to carbon nanomaterials is already taking place.
“There are potential technology-based solutions for replacing 13 out of the 14 metals by carbon nanomaterials in their most common applications. The technology development is at different stages for different metals and applications, but in some cases such as indium and gallium, the results are very promising,” Arvidsson says.
“This offers hope,” says Sandén. “In the debate on resource constraints, circular economy and society’s handling of materials, the focus has long been on recycling and reuse. Substitution is a potential alternative that has not been explored to the same extent and as the resource issues become more pressing, we now have more tools to work with.”
The research findings were recently published in the Journal of Cleaner Production. Arvidsson and Sandén stress that there are significant potential benefits from reducing the use of scarce metals, and they hope to be able to strengthen the case for more research and development in the field.
“Imagine being able to replace scarce metals with carbon,” Sandén says. “Extracting the carbon from biomass would create a natural cycle.”
“Since carbon is such a common and readily available material, it would also be possible to reduce the conflicts and geopolitical problems associated with these metals,” Arvidsson says.
At the same time they point out that more research is needed in the field in order to deal with any new problems that may arise if the scarce metals are replaced.
“Carbon nanomaterials are only a relatively recent discovery, and so far knowledge is limited about their environmental impact from a life-cycle perspective. But generally there seems to be a potential for a low environmental impact,” Arvidsson says.


Carbon nanomaterials consist solely or mainly of carbon, and are strong materials with good conductivity. Several scarce metals have similar properties. The metals are found, for example, in cables, thin screens, flame-retardants, corrosion protection and capacitors.
Rickard Arvidsson and Björn Sandén at Chalmers University of Technology have investigated whether the carbon nanomaterials graphene, fullerenes and carbon nanotubes have the potential to replace 14 scarce metals in their main areas of application (see table). They found potential technology-based solutions to replace the metals with carbon nanomaterials for all applications except for gold in jewellery. The metals which we are closest to being able to substitute are indium, gallium, beryllium and silver.

Here’s a link to and a citation for the paper,

Carbon nanomaterials as potential substitutes for scarce metals by Rickard Arvidsson, Björn A. Sandén. Journal of Cleaner Production (0959-6526). Vol. 156 (2017), p. 253-261. DOI: https://doi.org/10.1016/j.jclepro.2017.04.048

This paper appears to be open access.

Revolutionizing electronics with liquid metal technology?

I’m not sure I’d call it the next big advance in electronics, there are too many advances jockeying for that position but this work from Australia and the US is fascinating. From a Feb. 17, 2017 news item on ScienceDaily,

A new technique using liquid metals to create integrated circuits that are just atoms thick could lead to the next big advance for electronics.

The process opens the way for the production of large wafers around 1.5 nanometres in depth (a sheet of paper, by comparison, is 100,000nm thick).

Other techniques have proven unreliable in terms of quality, difficult to scale up and function only at very high temperatures — 550 degrees or more.

A Feb. 17, 2017 RMIT University press release (also on EurekAlert), which originated the news item, expands on the theme (Note: A link has been removed),

Distinguished Professor Kourosh Kalantar-zadeh, from RMIT’s School of Engineering, led the project, which also included colleagues from RMIT and researchers from CSIRO, Monash University, North Carolina State University and the University of California.

He said the electronics industry had hit a barrier.

“The fundamental technology of car engines has not progressed since 1920 and now the same is happening to electronics. Mobile phones and computers are no more powerful than five years ago.

“That is why this new 2D printing technique is so important – creating many layers of incredibly thin electronic chips on the same surface dramatically increases processing power and reduces costs.

“It will allow for the next revolution in electronics.”

Benjamin Carey, a researcher with RMIT and the CSIRO, said creating electronic wafers just atoms thick could overcome the limitations of current chip production.

It could also produce materials that were extremely bendable, paving the way for flexible electronics.

“However, none of the current technologies are able to create homogenous surfaces of atomically thin semiconductors on large surface areas that are useful for the industrial scale fabrication of chips.

“Our solution is to use the metals gallium and indium, which have a low melting point.

“These metals produce an atomically thin layer of oxide on their surface that naturally protects them. It is this thin oxide which we use in our fabrication method.

“By rolling the liquid metal, the oxide layer can be transferred on to an electronic wafer, which is then sulphurised. The surface of the wafer can be pre-treated to form individual transistors.

“We have used this novel method to create transistors and photo-detectors of very high gain and very high fabrication reliability in large scale.”

Here’s a link to and a citation for the paper,

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals by Benjamin J. Carey, Jian Zhen Ou, Rhiannon M. Clark, Kyle J. Berean, Ali Zavabeti, Anthony S. R. Chesman, Salvy P. Russo, Desmond W. M. Lau, Zai-Quan Xu, Qiaoliang Bao, Omid Kevehei, Brant C. Gibson, Michael D. Dickey, Richard B. Kaner, Torben Daeneke, & Kourosh Kalantar-Zadeh. Nature Communications 8, Article number: 14482 (2017) doi:10.1038/ncomms14482
Published online: 17 February 2017

This paper is open access.