Lab Profile: Chemical Physics of Low-Dimensional Nanostructures

Prof. Jonathan Coleman is the Principal Investigator of the Low-Dimensional Nanostructures group at Trinity College Dublin. His group’s research focuses on the study and application of nanomaterials including graphene, inorganic 2D nanosheets and carbon nanotubes. Jonathan is a speaker at this year’s New Scientist Live event, so Laurie Winkless spoke to him to learn more about his work…

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What is your academic background?

I came to Trinity College Dublin in 1991 for my undergrad in experimental physics, and I’ve never left! I first joined Prof. Werner Blau’s group to investigate carbon nanotubes in polymers, and I received my PhD in that topic in 1999. I was fortunate to then be awarded a Higher Education Authority Fellowship to continue my research into polymer-nanotube composites. In 2001, I became a lecturer in the School of Physics, and I worked my way up the ranks – I’m now a Professor and Fellow of Trinity College.

What are the major themes of your group’s research?

We focus on the development and application of low-dimensional (typically, 2D) nanostructures. A few years back, we developed a simple, but novel and scalable, method for producing 2D nanosheets of graphene, suspended in a solvent. We’ve since used this process – called liquid phase exfoliation – to produce large quantities of defect-free nanosheets from a range of layered materials. It not only represents a major breakthrough in terms of materials science, but it offers opportunities to a range of industries.

For example, future electric vehicles will need battery electrodes that offer much larger energy storage capacities – we’re now investigating how we can use molybdenum disulfide (MoS₂) to meet that challenge. We’re also working closely with medics to develop a graphene-rubber composites that can continuously measure blood pressure – something that has not been possible before now. Another area of interest is printed electronics. Graphene is a conductor, boron nitride is an insulator and MoS₂ is a semiconductor – by combining the three, we could produce small-scale, flexible devices by inject printing. The transistors we produce won’t necessarily be high performance, but they will be very cheap, so will have a big role in making the promised Internet of Things a reality.

How long has it been running? How large is it? What facilities and equipment does your lab have?

Originally, I worked within Prof Werner Blau’s group, but I have been an independent researcher since 2005. We now have around five postdoc research fellows within the group, along with eight or nine postgrads and a few undergrads – it varies, but the group always seems to be 15-20 researchers-strong. In terms of facilities, we have all of the standard wet chemistry stuff, along with numerous characterisation tools. We are lucky to have the incredible facilities at CRANN (the Centre for Research on Adaptive Nanostructures and Nanodevices) on our doorstep too.

What has been your highest impact work to date?

I think it’s safe to say that my highest impact work was the development of the liquid phase exfoliation method for processing 2D materials. What started off in our lab has since become a commercial technique used around the world. But there is another by-product of that work that I’m proud of, but which largely passed by unnoticed! There is a very famous equation in polymer chemistry, the Hildebrand-Scratchard equation, that everyone knows is wrong, but they’ve left it alone because it works. When trying to understand the mechanics of the solution process, we needed to develop that equation, so that it applied to 2D materials. But, as part of that analysis, we ended up finding the correct result for 1D materials, which is what polymer chains are.

What is the secret to running a successful lab?

For me, it’s all about looking after the team, and you don’t need to resort to an iron fist to do that. A group of people who are there just because they get paid to be there simply won’t discover anything new – it’s vital to have a happy team who are fully engaged in, and excited by, what they do. The individuals should be driven by curiosity for their own research, but they must also work well as part of a wider unit. Having a social bond is a key part of that, so coffee and/or pints outside of the lab are always encouraged!

How do you measure your progress as a group?

I guess the simplest measure is through papers. But it’s definitely not about just churning them out – we’re always on the hunt for work that is truly novel, and I think that usually leads to good papers. So much of research is about doing something that someone did before, but doing it slightly differently. I’m much more excited by new and exciting ideas, so as long as we’re coming up with those, I’m happy. We have a paper in review which is on a new class of composites for sensing. It’s totally different from what’s gone before, so different that when my student proposed it, I thought it was a bit silly. But I was happy to be wrong on this, and it will prove to be a very important discovery.

What does the future hold for your research?

Well, I could tell you about how excited I am by the medical sensor work, or talk about how important the Internet of Things will be, but ultimately, my goal is to show that nanoscience isn’t just something that academics have fun with. These materials, and the devices that we can make with them are already having a real, demonstrable societal impact, and they will continue to do so.

Collaborators

We are funded by Science Foundation Ireland, the European Research Council and the Graphene Flagship. We work closely with Nokia-Bell labs and a number of other companies.

Selected publications

1. Paton et al, Scalable production of large quantities of defect-free, few-layer graphene by shear exfoliation in liquids Nature Materials, 13, 624-630, 2014.

This paper describes the first scalable method for producing large quantities of high-quality graphene and will revolutionise graphene production. The IP associated with this work has been licenced by chemical firm, Thomas Swan. Graphene produced by this method will be commercially available from early summer 2014. It is anticipated that this work will facilitate the transition from lab-based to industrial applications of graphene. JNC was lead researcher and grant-holder for this work. [31 citations]

1. Coleman et al, Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials. Science 2011, 331 (6017), 568-571.

This paper demonstrates the first large-scale production method for inorganic 2-dimensional nanomaterials. This is widely considered as one of the papers that triggered the current boom in (non-carbon) 2-dimensional nanomaterials research. It is one of the highest cited papers in this field. JNC was the lead researcher and grant-holder on this project.  [968 citations]

1. Hernandez et al, High-yield production of graphene by liquid-phase exfoliation of graphite. Nature Nanotechnology 2008, 3 (9), 563-568.

This was the first work to describe a potentially large scale production method for graphene. This process is now widely viewed as one of the pillar methods for the production of graphene. JNC was the lead researcher and grant-holder on this project.  [1584 citations]

Further information

http://www.tcd.ie/Physics/research/groups/1d-nanostructures/

www.crann.tcd.ie/

http://ambercentre.ie/

http://www.tedxbrussels.eu/jonathan-coleman/