Smart Printed Electronics

Researchers in AMBER, the 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

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.

printed transistor

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transmit information: for example, milk cartons could send messages to your phone warning that the milk is about to go out-of-date.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.

The AMBER team’s findings have been published today in the journal Science*.


Self-Healable Lithium Ion Battery For Electronic Textile

Electronics that can be embedded in clothing are a growing trend. However, power sources remain a problem. In the journal Angewandte Chemie, scientists have now introduced thin, flexible, lithium ion batteries with self-healing properties that can be safely worn on the body. Even after completely breaking apart, the battery can grow back together without significant impact on its electrochemical properties.

Existing lithium ion batteries for wearable electronics can be bent and rolled up without any problems, but can break when they are twisted too far or accidentally stepped on—which can happen often when being worn. This damage not only causes the battery to fail, it can also cause a safety problem: Flammable, toxic, or corrosive gases or liquids may leak out.

A team led by Yonggang Wang and Huisheng Peng from  Fudan University in Shanghai – China, has now developed a new family of lithium ion batteries that can overcome such accidents thanks to their amazing self-healing powers. In order for a complicated object like a battery to be made self-healing, all of its individual components must also be self-healing. The scientists from Fudan University  the Samsung Advanced Institute of Technology (South Korea), and the Samsung R&D Institute China, have now been able to accomplish this.

self-healing-batteryThe electrodes in these batteries consist of layers of parallel carbon nanotubes. Between the layers, the scientists embedded the necessary lithium compounds in nanoparticle. In contrast to conventional lithium ion batteries, the lithium compounds cannot leak out of the electrodes, either while in use or after a break. The thin layer electrodes are each fixed on a substrate of self-healing polymer. Between the electrodes is a novel, solvent-free electrolyte made from a cellulose-based gel with an aqueous lithium sulfate solution embedded in it. This gel electrolyte also serves as a separation layer between the electrodes.

After a break, it is only necessary to press the broken ends together for a few seconds for them to grow back together. Both the self-healing polymer and the carbon nanotubes “stick” back together perfectly. The parallel arrangement of the nanotubes allows them to come together much better than layers of disordered carbon nanotubes. The electrolyte also poses no problems. Whereas conventional electrolytes decompose immediately upon exposure to air, the new gel is stable. Free of organic solvents, it is neither flammable nor toxic, making it safe for this application.

The capacity and charging/discharging properties of a batteryarmband” placed around a doll’s elbow were maintained, even after repeated break/self-healing cycles.


Super Capacitor for NanoComputer

VTT Technical Research Centre of Finland developed an extremely efficient small-size energy storage, a micro-supercapacitor, which can be integrated directly inside a silicon microcircuit chip. The high energy and power density of the miniaturized energy storage relies on the new hybrid nanomaterial developed recently at VTT. This technology opens new possibilities for integrated mobile devices and paves the way for zero-power autonomous devices required for the future Internet of Things (IoT).

Supercapacitors resemble electrochemical batteries. However, in contrast to for example mobile phone lithium ion batteries, which utilize chemical reactions to store energy, supercapacitors store mainly electrostatic energy that is bound at the interface between liquid and solid electrodes. Similarly to batteries supercapacitors are typically discrete devices with large variety of use cases from small electronic gadgets to the large energy storages of electrical vehicles.

The energy and power density of a supercapacitor depends on the surface area and conductivity of the solid electrodes. VTT‘s research group has developed a hybrid nanomaterial electrode, which consists of porous silicon coated with a few nanometre thick titanium nitride layer by atomic layer deposition (ALD). This approach leads to a record large conductive surface in a small volume. Inclusion of ionic liquid in a micro channel formed in between two hybrid electrodes results in extremely small and efficient energy storage.
nano capacitor 2

The new supercapacitor has excellent performance. For the first time, silicon based micro-supercapacitor competes with the leading carbon and graphene based devices in power, energy and durability.

Micro-supercapacitors can be integrated directly with active microelectronic devices to store electrical energy generated by different thermal, light and vibration energy harvesters and to supply the electrical energy when needed. This is important for autonomous sensor networks, wearable electronics and mobile electronics of the IoT.

VTT‘s research group takes the integration to the extreme by integrating the new nanomaterial micro-supercapacitor energy storage directly inside a silicon chip. The demonstrated in-chip supercapacitor technology enables storing energy of as much as 0.2 joule and impressive power generation of 2 watts on a one square centimetre silicon chip. At the same time it leaves the surface of the chip available for active integrated microcircuits and sensors.

VTT is currently seeking a party interested in commercializing the technique.


Nanotechnologies Boost Electric Car Batteries

On a drizzly, gray morning in April, Yi Cui weaves his scarlet red Tesla in and out of Silicon Valley traffic. Cui, a materials scientist at Stanford University here, is headed to visit Amprius, a battery company he founded 6 years ago. It’s no coincidence that he is driving a battery-powered car, and that he has leased rather than bought it. In a few years, he says, he plans to upgrade to a new model, with a crucial improvement: “Hopefully our batteries will be in it.” Cui and Amprius are trying to take lithium–ion batteries—today’s best commercial technology—to the next level. They have plenty of company. Massive corporations such as Panasonic, Samsung, LG Chem, Apple, and Tesla are vying to make batteries smaller, lighter, and more powerful. But among these power players, Cui remains a pioneering force.
Unlike others who focus on tweaking the chemical composition of a battery’s electrodes or its charge-conducting electrolyte, Cui is marrying battery chemistry with nanotechnology. He is building intricately structured battery electrodes that can soak up and release charge-carrying ions in greater quantities, and faster, than standard electrodes can, without producing troublesome side reactions.

Tesla Model 3

“He’s taking the innovation of nanotechnology and using it to control chemistry,” says Wei Luo, a materials scientist and battery expert at the University of Maryland, College Park.
In a series of lab demonstrations, Cui has shown how his architectural approach to electrodes can domesticate a host of battery chemistries that have long tantalized researchers but remained problematic. Among them: lithium-ion batteries with electrodes of silicon instead of the standard graphite, batteries with an electrode made of bare lithium metal, and batteries relying on lithium-sulfur chemistry, which are potentially more powerful than any lithium-ion battery. The nanoscale architectures he is exploring include silicon nanowires that expand and contract as they absorb and shed lithium ions, and tiny egglike structures with carbon shells protecting lithium-rich silicon yolks.


Brain Implant Moves Paralyzed Arm

This is Ian Burkhart of Ohio. His hands and legs were permanently paralyzed in a diving accident when he was 19 years old. But now with the help of a new, breakthrough computer chip implanted in his brain – the, now, 24-year-old is playing guitar hero.

brain implant helps paralized limbsCLICK ON THE IMAGE TO ENJOY THE VIDEO
When we first hooked everything up, you know for the first time being able to move my hand, it was a big shock because you know it was something that I have not moved in three and half years at that point, now it’s more of something where I expect it to move“,  says  Ian Burkhat, the quadriplegic patient at Ohio State University Wexner Medical Center.  The small pea-sized computer chip relays signals from Burkhart’s brain through 130 electrodes to his forearm, allowing his mind guide his hands and fingers, bypassing his damaged spinal cord. On Wednesday, scientists and neurosurgeons describing this quadriplegic’s accomplishments as a milestone in the evolution of brain-computer interface technology.

This really provides hope, we believe, for many patients in the future as this technology evolves and matures“, comments Doctor Ali Rezai, from the Ohio State’s Center for NeuroModulation. Burkhart says the progress is moving along faster than he imagined: “The biggest dream would be to get full function of my hand back, both my hands, because that would allow you to be much more independent, not to have to rely on people for simple day to day tasks that you take for granted.”

Scientists are working to improve the technology, which for now can only be used in the laboratory, and move toward a wireless system bringing Burkhart another step closer to his dream.


Robots That Feel And Touch Like Humans

Smart synthetic skins have the potential to allow robots to touch and sense what’s around them, but keeping them powered up and highly sensitive at low cost has been a challenge. Now scientists report in the journal ACS Nano a self-powered, transparent smart skin that is simpler and less costly than many other versions that have been developed.

mother robot

Endowing robots and prosthetics with a human-like sense of touch could dramatically advance these technologies. Toward this goal, scientists have come up with various smart skins to layer onto devices. But boosting their sensitivity has involved increasing the numbers of electrodes, depending on the size of the skin. This leads to a rise in costs. Other systems require external batteries and wires to operate, which adds to their bulk. Haixia Zhang and colleagues wanted to find a more practical solution.

The researchers created a smart skin out of ultra-thin plastic films and just four electrodes made from silver nanowires. Other prototypes contain up to 36 electrodes. Additionally, one component harvests mechanical energy — for example, from the movement of a prosthetic hand’s fingers — and turns it into an electric current.


Nanotechnology Improves Next Generation Of Batteries

In the global race to create more efficient and long-lasting batteries, some are betting on nanotechnology — the use of minuscule parts — as the most likely to yield a breakthrough. Improving batteries’ performance is key to the development and success of many much-hyped technologies, from solar and wind energy to electric cars. They need to hold more energy, last longer, be cheaper and safer. Research into how to achieve that has followed several avenues, from using different materials than the existing lithium-ion batteries to changing the internal structure of batteries using nanoparticles — parts so small they are invisible to the naked eye. Nanotechnology can increase the size and surface of batteries electrodes, the rods inside the batteries that absorb the energy. It does so by effectively making the electrodes sponge-like, so that they can absorb more energy during charging and ultimately increasing the energy storage capacity. Prague-based company HE3DA in Czech Republic has developed such a technology by using the nanotechnology to move from the current flat electrodes to make them three dimensional. With prototypes undergoing successful testing, it hopes to have the battery on the market at the end of this year.

Tesla Model 3

In the future, this will be the mainstream,” said Jan Prochazka, the president. He said it would be targeted at high-intensity industries like automobiles and the energy sector, rather than mobile phones, because that is where it can make the biggest difference through its use of his bigger electrodes.

In combination with an internal cooling system the batteries, which are being tested now, should be safe from overheating or exploding, a major concern with existing technologies. Researchers at the University of Michigan and MIT have likewise focused on nanotechnology to improve the existing lithium-ion technology. Others have sought to use different materials. One of the most promising is lithium oxygen, which theoretically could store five to 10 times the energy of a lithium ion battery, but there have been a number of technical problems that made it inefficient. Batteries based on sodium-ion, aluminium-air and aluminium-graphite are also being explored. There’s even research on a battery powered by urine.


Bionic Finger Feels Texture

An amputee was able to feel smoothness and roughness in real-time with an artificial fingertip that was surgically connected to nerves in his upper arm. Moreover, the nerves of non-amputees can also be stimulated to feel roughness, without the need of surgery, meaning that prosthetic touch for amputees can now be developed and safely tested on intact individuals.

The technology to deliver this sophisticated tactile information was developed by Silvestro Micera and his team at EPFL (Ecole polytechnique fédérale de Lausanne) and SSSA (Scuola Superiore Sant’Anna) together with Calogero Oddo and his team at SSSA. The results, published today in eLife, provide new and accelerated avenues for developing bionic prostheses, enhanced with sensory feedback.


“The stimulation felt almost like what I would feel with my hand,” says amputee Dennis Aabo Sørensen about the artificial fingertip connected to his stump. He continues, “I still feel my missing hand, it is always clenched in a fist. I felt the texture sensations at the tip of the index finger of my phantom hand.

Sørensen is the first person in the world to recognize texture using a bionic fingertip connected to electrodes that were surgically implanted above his stump.

Nerves in Sørensen’s arm were wired to an artificial fingertip equipped with sensors. A machine controlled the movement of the fingertip over different pieces of plastic engraved with different patterns, smooth or rough. As the fingertip moved across the textured plastic, the sensors generated an electrical signal. This signal was translated into a series of electrical spikes, imitating the language of the nervous system, then delivered to the nerves.

Sørensen could distinguish between rough and smooth surfaces 96% of the time.


Brain: Graphene Interacts Safely With Neurons

Researchers from the University of Trieste (Italy) and the University of Cambridge have successfully demonstrated how it is possible to interface graphene – a two-dimensional form of carbon – with neurons, or nerve cells, while maintaining the integrity of these vital cells. The work may be used to build graphene-based electrodes that can safely be implanted in the brain, offering promise for the restoration of sensory functions for amputee or paralysed patients, or for individuals with motor disorders such as epilepsy or Parkinson’s disease. Previously, other groups had shown that it is possible to use treated graphene to interact with neurons. However the signal to noise ratio from this interface was very low. By developing methods of working with untreated graphene, the researchers retained the material’s electrical conductivity, making it a significantly better electrode.

graphene interacts in the brain

For the first time we interfaced graphene to neurons directly,” said Professor Laura Ballerini of the University of Trieste in Italy. “We then tested the ability of neurons to generate electrical signals known to represent brain activities, and found that the neurons retained their neuronal signalling properties unaltered. This is the first functional study of neuronal synaptic activity using uncoated graphene based materials.

The research, published in the journal ACS Nano, was an interdisciplinary collaboration coordinated by the University of Trieste in Italy and the Cambridge Graphene Centre.


How To Detect Alzheimer’s Years Before Memory Loss

Chilean neurologists say they’ve found a key to diagnosing Alzheimer’s disease early, even before memory loss and other symptoms develop. Researchers at Chile’s Biomedical Neuroscience Institute (BNI) believe they can identify early stages of dementia and other psychiatric diseases in sufferers through observing eye movement patterns and the brain’s electrical activity. The neurologists study patients navigating a virtual location, where they must find “keys” to complete a task. Lead neurologist Enzo Brunetti said the tests were able to detect very early signs of cognitive impairment in patients who apparently presented no symptoms of Alzheimer’s.

Eye movement link to Alzheimer's

Eye movements and brain activity may be the key to diagnosing Alzheimer’s disease earlier and more accurately, according to research led by Chilean neurologists.

In this study, what we did was that we applied spatial navigation tasks using a computer, and with the help of a software we examined in detail which were the early functions that became altered in Alzheimer’s disease (patients) and focused on a very specific function, linked to the codification and development of cognitive memory, that helps people move through the physical environment. This is one of the cognitive functions that were altered in patients with Alzheimer’s and we observed that they were altered from very early stages. Therefore we believe this is a biomarker for the disease, which would give us an opportunity to shed light on an early diagnosis for this disease“, says Enzo Brunetti, neurologist.
Brunetti says the patients who are likely to develop some form of dementia make similar eye movements while navigating through the virtualroom” to those at a developed stage of the disease. With the help of electrodes that measure the brain’s electrical activity, the neurologists run non-invasive electroencephalogram (EEG) tests on patients while they navigate through the computer-made universe.
More tests and a larger clinical trial are needed before the treatment can be made available. An early Alzheimer’s diagnosis may not only help patients and their families plan better for the future, but also offer them a possibility of delaying the symptoms with drugs and other existing treatments. Alzheimer’s is very difficult to detect until it has progressed from mild memory loss to clear impairment. Patients eventually lose all ability to care for themselves.


Electric Cars: How To Improve Batteries

One big problem faced by electrodes in rechargeable batteries, as they go through repeated cycles of charging and discharging, is that they must expand and shrink during each cycle — sometimes doubling in volume, and then shrinking back. This can lead to repeated shedding and reformation of its “skin” layer that consumes lithium irreversibly, degrading the battery’s performance over time.

Image with 2014 Renault

Image with 2014 Renault

Now a team of researchers at MIT and Tsinghua University in China has found a novel way around that problem: creating an electrode made of nanoparticles with a solid shell, and a “yolk” inside that can change size again and again without affecting the shell. The innovation could drastically improve cycle life, the team says, and provide a dramatic boost in the battery’s capacity and power.

The new findings, which use aluminum as the key material for the lithium-ion battery’s negative electrode, or anode, are reported in the journal Nature Communications, in a paper by MIT professor Ju Li and six others. The use of nanoparticles with an aluminum yolk and a titanium dioxide shell has proven to be “the high-rate champion among high-capacity anodes,” the team reports.


Low Cost Water Splitter For Hydrogen Fuel Cells

Stanford University scientists have created a silicon-based water splitter that is both low-cost and corrosion-free. The novel device – a silicon semiconductor coated in an ultrathin layer of nickel – could help pave the way for large-scale production of clean hydrogen fuel from sunlight, according to the scientists.

splitting waterThis image shows two electrodes connected via an external voltage source splitting water into oxygen (O2) and hydrogen (H2). The illuminated silicon electrode (left) uses light energy to assist in the water-splitting process and is protected from the surrounding electrolyte by a 2-nm film of nickel

Solar cells only work when the sun is shining,” said study co-author Hongjie Dai, a professor of chemistry at Stanford. “When there’s no sunlight, utilities often have to rely on electricity from conventional power plants that run on coal or natural gas.”
A greener solution, Dai explained, is to supplement the solar cells with hydrogen-powered fuel cells that generate electricity at night or when demand is especially high.
The results are published in the Nov. 15 issue of the journal Science.