Graphene applications: what is graphene used for? - Page 24

Scientists from Nanyang Technological University (NTU), Panasonic Factory Solutions Asia Pacific Pte. Ltd. (Panasonic) and Singapore Centre for 3D Printing (SC3DP) have developed a multi-material printer using multi-wavelength high-power lasers, for quick and easy 3D printing of smart, flexible devices.

The multi-material printer works by utilizing varying wavelengths of laser, creating thermal and chemical reactions capable of transforming common carbon-based materials (polyimide and graphene oxide) into a new type of highly porous graphene. The resulting structure printed with this new graphene is not only light and conductive, but it can also be printed or coated onto flexible substrates like plastics, glass, gold and fabrics, creating flexible devices.

Singapore-based ship management company, Eastern Pacific Shipping (EPS), has announced that it has teamed up with Canada-based coatings company Graphite Innovation & Technologies  (GIT) to implement its graphene-based, biocide-free propeller coating across its fleet.

EPS plans to boost the performance of its vessels by applying GIT’s eco-friendly, highly durable, and ultra-low friction foul release coating, aiming to improve and maintain CII rating over the drydocking cycle.

Researchers at Queen Mary University, University of Sussex and University of Brighton have integrated graphene into seaweed to create nanocomposite microcapsules for highly tunable and sustainable epidermal electronics. When assembled into networks, the tiny capsules can record muscular, breathing, pulse, and blood pressure measurements in real-time with ultrahigh precision.

The team explained that much of the current research on nanocomposite-based sensors is related to non-sustainable materials. This means that these devices contribute to plastic waste when they are no longer in use. The new study shows that it is possible to combine molecular gastronomy concepts with biodegradable materials to create such devices that are not only environmentally friendly, but also have the potential to outperform the non-sustainable ones.

Graphene is known to have an extremely quick response to incoming light, which leads scientists to believe it can potentially lead to applications like ultrafast photodetectors that could meet the ever-growing demand for internet bandwidth. However, graphene's exceptional thinness means that it absorbs light poorly, typically tapping only about 2% of a laser beam’s energy.

Now, scientists from Switzerland's ETH Zurich have shown how graphene’s speed might be exploitable after all, by integrating it with a tailor-made infrared absorber—a metamaterial consisting of an array of tiny gold antennas. The researchers have reportedly demonstrated a world-record photodetection bandwidth of 500 GHz combined with a flat frequency response across a broad part of the near-infrared spectrum. Although the device’s overall absorption still remains fairly low, they believe that its ability to deal with high input powers combined with further design optimizations could enable a new generation of graphene-based photodetectors.

Researchers from California Institute of Technology (Caltech), The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, University of California Los Angeles and Cedars-Sinai Medical Center have designed a wearable and wireless patch for the real-time electrochemical detection of the inflammatory biomarker C-reactive (CRP) protein in sweat. CRP is secreted by the liver and is commonly associated with inflammation. Its presence in the bloodstream strongly indicates an underlying health condition. CRP is much more difficult to detect because it is at a much lower concentration than other biomarkers.

The device integrates iontophoretic sweat extraction, microfluidic channels for sweat sampling and for reagent routing and replacement, and a graphene-based sensor array for quantifying CRP (via an electrode functionalized with anti-CRP capture antibodies-conjugated gold nanoparticles), ionic strength, pH and temperature for the real-time calibration of the CRP sensor.

Zentek recently announced a new research and development contract through Innovative Solutions Canada to test ZenARMOR™ nano-pigment in military grade, chromate-free, corrosion protection aerospace paint systems.

The testing will be conducted under the supervision of Dr. Qi Yang, and Dr. Naiheng Song, Research Officers at the National Research Council of Canada (NRC) Aerospace Research Centre’s Aerospace Manufacturing Technologies Centre (AMTC).

Researchers from Arizona State University (ASU) have presented a design concept for enhanced saturable absorption effect based on subwavelength-thick (<1/5λ0) hybrid graphene-plasmonic metasurface structures in infrared wavelengths. Yu Yao and her research team at the ASU Center for Photonics Innovation designed a faster and more energy-efficient nanoscale laser component called the graphene-plasmonic hybrid metastructure saturable absorber, known as GPSMA.

The team's theoretical and experimental results demonstrated that, by exciting nonequilibrium carriers inside nanoscale hotspots, one could not only enhance the saturable absorption in graphene, but also reduce the saturation fluence by over 3 orders of magnitude (from ∼1 mJ/cm² to ∼100 nJ/cm²). Their pump–probe measurement results suggested an ultrashort saturable absorption recovery time (<60 fs), which is ultimately determined by the relaxation dynamics of photoexcited carriers in graphene. They also observed pulse narrowing effects in the devices based on the autocorrelation measurement results. Such design concepts can be tailored via structure engineering to operate in broader wavelength ranges up to mid- and far- infrared spectral regions. These ultrafast low-saturation fluence saturable absorber designs can enable low-threshold, compact, self-starting mode-locked lasers, laser pulse shaping, and high-speed optical information processing.

Researchers from Helmholtz-Zentrum Dresden-Rossendorf, Catalan Institute of Nanoscience and Nanotechnology (ICN2) and the University of Exeter have demonstrated that the properties and dynamics of electronic heat in graphene allow for a THz-to-visible conversion, which is switchable at a sub-nanosecond time scale. The results show that graphene-based materials can be used to efficiently convert high-frequency signals into visible light.

The team showed a tunable on/off ratio of more than 30 for the emitted visible light, achieved through electrical gating using a gate voltage on the order of 1 V. They also demonstrated that a grating-graphene metamaterial leads to an increase in THz-induced emitted power in the visible range by 2 orders of magnitude. These recent results could provide a route towards novel functionalities of optoelectronic technologies in the THz regime.

DARPA, Siemens, the U.S ARMY, Georgia Tech Research Institute and Paragraf - through recently acquired Cardea Bio, now Paragraf San Diego - have presented novel multiomics capabilities, by detection of both protein and RNA biosignals simultaneously on a single graphene-based biosensor.

It was stated that this achievement marks the first public demonstration of this novel methodology for multiomics and that the paper is the first in the world demonstrating the capability to detect both protein and RNA biosignals in a COVID-19 based experiment where both the COVID wild type as well as the Omicron variant were successfully detected.

Researchers from Purdue University have developed patent-pending, solid-state, continuously tunable thermal devices based on compressible graphene foam composites. The devices can dissipate heat, insulate against cold and function across a wide range of temperatures. 

The devices have the potential to improve battery safety and performance in electronic devices and systems like battery thermal management, space conditioning, vehicle thermal comfort and thermal energy storage.