Graphene Flagship: Europe's $1 billion graphene initiative - Page 10

Researchers at Chalmers University, affiliated with the Graphene Flagship, have devised a graphene-based spin field-effect transistor with the ability to function at room temperature. The team used the spin of electrons in graphene and similar layered material heterostructures to fabricate working devices in a step towards combining memory devices and the logic of spintronics.

The researchers demonstrated that the spin characteristics of graphene can be electrically regulated in a controlled way, even at an ambient temperature. In addition to possibly unlocking various probabilities in spin logic operations, this study also enables integration with magnetic memory elements in a device unit. If further advancements can assist in the production of a spin current without the need for charge flow, the amount of power needed will be considerably reduced, resulting in highly versatile devices.

The Graphene Flagship has announced preparations for two new experiments in collaboration with the European Space Agency (ESA), to test the viability of graphene for space applications. Both experiments will launch between 6-17th November 2017, testing graphene in zero-gravity conditions to determine its potential in space applications.

One of the two experiments (named GrapheneX) will be fully student-led, by a team of Graphene Flagship graduate students from Delft Technical University in the Netherlands. The team will use microgravity conditions in the ZARM Drop Tower (Bremen, Germany) to test graphene for light sails. By shining laser light on suspended graphene-membranes from Flagship partner Graphenea, the experiment will test how much thrust can be generated, which could lead to a new way of propelling satellites in space using light from lasers or the sun.

An international team of scientists collaborating in the Graphene Flagship project has developed a graphene-based transistor that reportedly outperforms previous state-of-the-art ones. The team utilized a thin top gate insulator material to optimize operational properties like maximum oscillation frequency, cutoff frequency, forward transmission coefficient, and open-circuit voltage gain, realizing devices that show prospect of using graphene in a wide range of electronic applications.

Graphene lack of a bandgap hinders its use in electronics since it causes an inability to switch the transistors off, effectively rendering the 0 state in digital logic inaccessible. However, many analog applications do not require a bandgap; The team explains that the only undesired side-effect of using GFETs in analog circuits is a poor saturation of the drain current, which prevents high-gain operation. The researchers have now succeeded in improving saturation by optimizing the dielectric material (AlOx) that is used to electrically insulate the top gate of the GFET. An improved quality of gate dielectric resulted in strong control over carriers in the graphene channel, yielding overall performance benefits.

Graphene Flagship researchers from AMBER at Trinity College Dublin, in collaboration with scientists from TU Delft, Netherlands, have fabricated printed transistors consisting entirely of layered materials. The team's findings are said to have the potential to cheaply print a range of electronic devices from solar cells to LEDs and more.

The team used standard printing techniques to combine graphene flakes as the electrodes with other layered materials, tungsten diselenide and boron nitride as the channel and separator to form an all-printed, all-layered materials, working transistor.

Researchers from the Graphene Flagship have developed a new graphene-based device able to record brain activity in high resolution while maintaining excellent signal to noise ratio (SNR). Based on graphene field-effect transistors, the flexible devices have to potential to open up new possibilities for the development of functional implants and interfaces.

Neural activity is detected through the electric fields generated when neurons fire. These fields are highly localized, so having ultra-small measuring devices that can be densely packed is important for accurate brain readings. The graphene-based probes are reportedly competitive with state-of-the-art platinum electrode arrays and have the benefits of intrinsic signal amplification and a better signal-to-noise performance when scaled down to very small sizes. This will allow for more densely packed and higher resolution probes, vital for precision mapping of brain activity. The inherent amplification property of the transistor also removes the need for a pre-amplification close to the probe a requirement for metal electrodes.

Researchers at the Centre for Hybrid and Organic Solar Energy (CHOSE) of the University of Rome Tor Vergata, along with researchers at the Italian Institute of Technology (IIT) and the University of Applied Sciences in Crete (TEI), have stated that they set a new record for conversion efficiency of a perovskite photovoltaic module with an area larger than 50 cm².

The success was achieved as part of Graphene Flagship, the 1 billion euro European project that promotes graphene-based innovation in sectors like energy, electronics, technology and medicine. Perovskites photovoltaic modules' efficiency is usually demonstrated in the laboratory on cells less than 1 cm² in size, whereas the new test was performed on modules with an area larger than 50 cm². The electronic and chemical properties offered by graphene have made it possible to overcome the many difficulties related to the realization of large-area perovskite solar panels.

Researchers at the Cambridge Graphene Centre at the University of Cambridge, UK, have designed a method for producing high quality conductive graphene inks with high concentrations. Conductive inks are useful for a range of applications, including printed and flexible electronics, transistors, and more.

The method uses ultrahigh shear forces in a microfluidization process to exfoliate graphene flakes from graphite. The process is said to convert 100% of the starting graphite material into usable flakes for conductive inks, avoiding the need for centrifugation and reducing the time taken to produce a usable ink. The research also describes optimization of the inks for different printing applications, as well as giving detailed insights into the fluid dynamics of graphite exfoliation.

Researchers from the Graphene Flagship, working at the University of Cambridge (UK), Emberion (UK), the Institute of Photonic Sciences (ICFO; Spain), Nokia UK, and the University of Ioannina (Greece) have developed a novel graphene-based pyroelectric bolometer - an infrared (IR) detector with record high sensitivity for thermal detection, capable of resolving temperature changes down to a few tens of µK. This work may open the door to high-performance IR imaging and spectroscopy.

The technology is focused on the detection of the radiation generated by the human body and its conversion into a measurable signal. The key point is that using graphene, the conversion reaches performance more than 250 times better than the best sensor already available. But the high sensitivity of the detector could be of use for spectroscopic applications beyond thermal imaging. With a high-performance graphene-based IR detector that gives a strong signal with less incident radiation, it is possible to isolate different parts of the IR spectrum. This is of key importance in security applications, where different materials explosives, for instance can be distinguished by their characteristic IR absorption or transmission spectra.

The Spain-based Avanzare, nanomaterials and nanotechnology-based solutions provider and Graphene Flagship partner, has introduced to the market a graphene additive for industrial resins used for corrosion-resistant tanks and pipes for storage and transport of potentially explosive chemicals. Their product will be showcased at the Composites Europe exhibition, running from the 29 November to 1 December in Düsseldorf, Germany.

The company's graphene-based product can be used to help avoid explosions due to electrostatic charges. Avanzare aims to produce vessels and equipment using resins instead of the usual metals; These resins are also cheaper, lighter and have very good corrosion resistance. The graphene-resin, claimed to already be in use in high-volume industry applications, was developed by Avanzare through a collaboration with Ashland, an international chemical manufacturing company. According to company reports, the graphene-resin is already in use in chemical plants across Europe, and Ashland has installed graphene-resin systems in their facilities in Spain.

The Graphene Flagship's Italian partner CNR-ISOF has found that it is possible to use graphene to produce fully flexible NFC antennas. By combining material characterization, computer modelling and engineering of the device, the Graphene Flagship researchers designed an antenna that could exchange information with near-field communication devices such as a mobile phone, matching the performance of conventional metallic antennas.

The graphene-based NFC antennas are chemically inert, highly resistant to thousands of bending cycles and can be deposited on different standard polymeric substrates or silk tissues. The fully flexible graphene NFC device demonstrators were tested with a smartphone through the NFC reader App by the Graphene Flagship partner STMicroelectronics, showing good functionality whether flat or fixed on curved objects.