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Researchers in AMBER, the Science Foundation Ireland-funded materials science research centre hosted in Trinity College Dublin, have fabricated printed transistors consisting entirely of 2-dimensional nanomaterials for the first time. These 2D materials combine exciting electronic properties with the potential for low-cost production. This breakthrough could unlock the potential for applications such as food packaging that displays a digital countdown to warn you of spoiling, wine labels that alert you when your white wine is at its optimum temperature, or even a window pane that shows the day’s forecast. The AMBER team’s findings have been published today in the leading journal Science*.

This discovery opens the path for industry, such as ICT and pharmaceutical, to cheaply print a host of electronic devices from solar cells to LEDs with applications from interactive smart food and drug labels to next-generation banknote security and e-passports.

Prof Jonathan Coleman, who is an investigator in AMBER and Trinity’s School of Physics, said, “In the future, printed devices will be incorporated into even the most mundane objects such as labels, posters and packaging.
Printed electronic circuitry (constructed from the devices we have created) will allow consumer products to gather, process, display and transmit information: for example, milk cartons could send messages to your phone warning that the milk is about to go out-of-date.

We believe that 2D nanomaterials can compete with the materials currently used for printed electronics. Compared to other materials employed in this field, our 2D nanomaterials have the capability to yield more cost effective and higher performance printed devices. However, while the last decade has underlined the potential of 2D materials for a range of electronic applications, only the first steps have been taken to demonstrate their worth in printed electronics. This publication is important because it shows that conducting, semiconducting and insulating 2D nanomaterials can be combined together in complex devices. We felt that it was critically important to focus on printing transistors as they are the electric switches at the heart of modern computing. We believe this work opens the way to print a whole host of devices solely from 2D nanosheets.”

Led by Prof Coleman, in collaboration with the groups of Prof Georg Duesberg (AMBER) and Prof. Laurens Siebbeles (TU Delft,Netherlands), the team used standard printing techniques to combine graphene nanosheets as the electrodes with two other nanomaterials, tungsten diselenide and boron nitride as the channel and separator (two important parts of a transistor) to form an all-printed, all-nanosheet, working transistor.

Printable electronics have developed over the last thirty years based mainly on printable carbon-based molecules. While these molecules can easily be turned into printable inks, such materials are somewhat unstable and have well-known performance limitations. There have been many attempts to surpass these obstacles using alternative materials, such as carbon nanotubes or inorganic nanoparticles, but these materials have also shown limitations in either performance or in manufacturability. While the performance of printed 2D devices cannot yet compare with advanced transistors, the team believe there is a wide scope to improve performance beyond the
current state-of-the-art for printed transistors.

The ability to print 2D nanomaterials is based on Prof. Coleman’s scalable method of producing 2D nanomaterials, including graphene, boron nitride, and tungsten diselenide nanosheets, in liquids, a method he has licensed to Samsung and Thomas Swan. These nanosheets are flat nanoparticles that are a few nanometres thick but hundreds of nanometres wide. Critically, nanosheets made from different materials have electronic properties that can be conducting, insulating or semiconducting and so include all the building blocks of electronics. Liquid processing is especially advantageous in that it yields large quantities of high quality 2D materials in a form that is easy to process into inks. Prof. Coleman’s publication provides the potential to print circuitry at extremely low cost which will facilitate a range of applications from animated posters to smart labels.

Prof Coleman is a partner in Graphene flagship, a €1 billion EU initiative to boost new technologies and innovation during the next 10 years.

* All-printed thin-film transistors from networks of liquid-exfoliated nanosheets, Science, 7th April 2017

Ground-breaking research led by Prof Stefano Sanvito, Director of the CRANN Institute at Trinity College Dublin and Investigator in the Science Foundation Ireland funded centre AMBER, has demonstrated how molecular magnets could be used successfully in applications such as hard-disk drives and quantum computers. The breakthrough could increase a computer hard-disk’s capacity by 1000 using tiny molecules. How this might work has stymied international researchers for over thirty years, due to the challenge of molecular magnets operating at room temperature. This discovery could one day revolutionise computation as we know it, enabling lengthy and complex calculations, such as database searches, to be performed at incredibly high speeds.

In a paper published in the prestigious journal Nature Communications, the AMBER team comprising Prof Sanvito and Dr Alessandro Lunghi working with Prof Roberta Sessoli and her team at the University of Firenze, Italy, have discovered that by engineering the molecules to be as rigid as possible, they can operate at room temperature, thus opening up new ways for designing high-performance molecular magnets.

Molecular magnets are tiny molecules, often comprising only a handful of atoms, which display the same properties of conventional magnets, such as iron. If molecular magnets were to be used as bits in hard-disk drives, there is the potential to increase the disk’s capacity up to a thousand times, so that standard 3.5’ hard-disk would store more than 1,000,000 gigabytes of data. This is because molecular magnets can be packed together at ultra-high density. Furthermore, other possible applications for magnetic magnets operating at high temperature are in quantum technologies such as quantum computation.

At present a hypothetical hard-disk made of magnetic molecules will lose all data unless cooled down to about -200 C. Over the years researchers have been working very hard to design these molecules to operate at room temperature, mostly focussing their attention on magnetic properties.

Prof Stefano Sanvito, Director of CRANN and Investigator at AMBER and Trinity’s School of Physics said, “This is a very exciting breakthrough and something that is of huge interest to the scientific community, who have demonstrated very slow progress to date with the development of molecular magnets that can operate at room temperature. When a magnet is small its magnetic properties degrade rapidly with temperature. In this paper, we have shown that a drastic improvement in the high-temperature properties of magnetic magnets can be achieved by engineering the molecules to be as rigid as possible.”

This discovery will allow progress in the design of high-performance molecular magnets, a task already on-going in Prof Sessoli’s lab, and offers real potential for a quantum technologies, such as quantum computers. These may one day revolutionise computation as we know it, enabling lengthy and complex calculations, such as database searches, to be performed at incredibly high speeds.

Irish scientists are developing an advanced technology to speed up bone repair in adults who have suffered severe fractures and bone degeneration. This follows the identification of a gene which explains why children’s stem cells form bone very quickly.

Scientists at RCSI (Royal College of Surgeons in Ireland) and SFI funded AMBER (Advanced Materials and BioEngineering Research) centre, in collaboration with clinicians at the National Paediatric Craniofacial Centre (NPCC) at Temple Street Children’s University Hospital, compared children and adult-derived stem cells in order to understand more comprehensively why children’s cells have an extraordinary capacity to respond to their environment and repair bone quickly.
Their study investigated the age-associated changes in the capacity of stem cells to form bone tissue, and identified a potential therapeutic target which opens new avenues to develop novel therapeutic target-specific biomaterials for restoring a child-like bone healing capacity in adults suffering from severe fractures and bone degeneration.
The RCSI and AMBER team carried out the study with Mr. Dylan Murray, lead clinician at the NPCC at Temple Street Children’s University Hospital.

In this study the researchers found that children’s stem cells are far more sensitive to changes in their physical environment and form bone quicker than adult-derived stem cells. Furthermore, by comparing the genetic expression of children and adult-derived stem cells, the researchers identified a particular gene (JNK3) that explains why children’s stem cells respond to their physical environment differently, creating more bone than adult cells, thus, suggesting its potential as a new target to promote enhanced bone repair. Building on a wealth of experience in advanced biomaterials in the RCSI Tissue Engineering Research Group (TERG), the team is now utilising this knowledge to develop an advanced technology to facilitate enhanced bone repair.

Professor Fergal O’Brien from the Department of Anatomy in RCSI who is lead-Principal Investigator on the project and Deputy Director of AMBER said: ‘We are very excited by the identification of a key mechanism which influences bone formation in children and this study opens a new research avenue which will focus on therapeutic delivery in order to upregulate this gene with a view to replicating the enhanced bone regenerative potential of children in adults. Ultimately we hope that this research will lead to improved treatments for patients who have suffered severe bone loss through injury or disease’.

Commenting on the significance of the research, Dr Arlyng Gonzalez Vazquez, joint first author on the study said: ‘Our findings not only have major implications for tackling the decrease of bone repair capacity that occurs with age but also set the basis for a novel research strategy applicable to other tissues in the body’.

The research, which has just been published in Acta Biomaterialia – a leading journal in the biomedical engineering field, was the result of a multi-disciplinary effort between cell biologists, clinicians and engineers in the RCSI TERG and €58million SFI-funded AMBER Centre. Post-doctoral researchers, Dr Arlyng Gonzalez Vazquez and Dr Sara Barreto, the first authors on the study conducted the research under the supervision of Professor O’Brien in RCSI and Mr. Dylan Murray in Temple Street. This work was supported by the Health Research Board, the Temple Street Foundation (the fundraising arm of the hospital) and the Irish Research Council.

RCSI is ranked in the top 250 institutions worldwide in the Times Higher Education World University Rankings (2016-2017). It is an international not-for-profit health sciences institution, with its headquarters in Dublin, focused on education and research to drive improvements in human health worldwide.

Professor John Donegan from the School of Physics in Trinity College Dublin has been awarded €1.46m through Science Foundation Ireland’s Principal Investigator scheme. The funding will be used to investigate how laser technology could deliver more energy efficient devices for future optical networks. This will potentially lead to broadband speeds exceeding 100 Mb per second. This research is of particular interest to the ICT sector. Nokia Bell Labs have a keen interest in the project as the energy efficient devices being examined will likely complement the collaborative research activities they are currently undertaking with Prof Donegan’s team.

Optical networks use light to transmit information and are a critical part of the world’s Internet infrastructure. These optical networks currently use about 1% of the world’s total electricity supply, but the growth rate is immense and projections suggest it could reach 5% by 2022. For this reason, there is an urgent need to tackle the energy requirements of communications networks. Professor Donegan’s research will examine the individual semiconductor lasers that currently light up global optical networks and will attempt to develop lasers that can operate at a range of temperatures without changing wavelength –one of the main contributing factors to energy usage in optical networks. Professor Donegan’s approach is unique in this research field.

Professor Donegan, commenting on the award, said: “The world as we know it depends critically on the wired internet for communications. Each day, billions of e-mail and webpages traverse the net and there is a substantial cost in operating this network. A major impediment to growth in the future is the electrical power required to operate the net. Our research will investigate a range of new laser structures that operate with much improved efficiency and I look forward to further testing our devices with industry.

“These lasers are quite efficient, but still require an in-built cooling system to keep the laser at a precise wavelength. Since hundreds of lasers operate on the network, they cannot be allowed to shift wavelength when they operate. The challenge therefore is to develop lasers that are “athermal”, i.e. operate at a range of temperatures but do not change wavelength. This is the research challenge that we will address with this funding. The research team will also look at a range of different semiconductor laser structures and work on the integration of new materials sets, coupling semiconductors, oxides and polymers, into the standard materials for optical communications lasers.”

Professor Donegan is an Investigator in two Science Foundation Ireland research centres in Trinity: AMBER, the materials science research centre, and CONNECT, the centre for future networks and communications. This award, which will benefit both centres, will run until 2022 and will support a team of five researchers, two post-doctoral researchers and three graduate students.