Electronics - Page 5

Graphenest and Hubron recently announced they have entered a strategic partnership to explore the development and commercialization of graphene-based polymer masterbatch and compounds with unprecedented electromagnetic interference (EMI) shielding performance for electronic enclosures manufacturing. 

The companies explained that this new product line will start with a graphene-based thermoplastic suitable to be implemented as a remarkable EMI shielding solution in medium-high and high frequencies (for 5G and beyond).

Researchers from Carnegie Mellon University and MIT have demonstrated a 3D graphene-nanowire “sandwich” thermal interface that enables an ultralow thermal resistance of ∼0.24 mm2·K/W that is about 1 order of magnitude smaller than those of solders and several orders of magnitude lower than those of thermal greases, gels, and epoxies.

In addition, the new 3D graphene-nanowire “sandwich” thermal interface also boasts a low elastic and shear moduli of ∼1 MPa like polymers and foams. It exhibits excellent long-term reliability with >1000 cycles over a broad temperature range from −55 °C to 125 °C. This nanostructured thermal interface material can greatly benefit a variety of electronic systems and devices by allowing them to operate at lower temperatures or at the same temperature but with higher performance and higher power density.

Researchers from China's Xi’an Polytechnic University, Tsinghua University, Chinese Academy of Sciences CAS) and Shaanxi Textile Research Institute have found that breathable electrodes woven into fabric used in fire suits have proven to be stable at temperatures over 520ºC. At these temperatures, the fabric is found to be essentially non-combustible with high rates of thermal protection time at the maximum values recorded so far for such technology at 18.91 seconds.

The results show the efficacy and practicality of Janus graphene/poly(p-phenylene benzobisoxazole), or PBO, woven fabric in making firefighting “smarter”, with aims to manufacture products on an industrial scale that are flame-retardant but also intelligent enough to warn the firefighter of increased risks while facing flames.

Researchers from Georgia Institute of Technology, National High Magnetic Field Laboratory, Tianjin University, CNRS and Kwansei Gakuin University have developed a new graphene-based nanoelectronics platform compatible with conventional microelectronics manufacturing, potentially paving the way for a successor to silicon.
    
Walter de Heer, Regents' Professor in the School of Physics at the Georgia Institute of Technology, and his collaborators, have developed a new nanoelectronics platform based on graphene. The technology is compatible with conventional microelectronics manufacturing, a necessity for any viable alternative to silicon. In the course of their research, the team may have also discovered a new quasiparticle. Their discovery could lead to manufacturing smaller, faster, more efficient, and more sustainable computer chips, and has potential implications for quantum and high-performance computing.

Researchers from Monash University, The University of Melbourne and RMIT University have shown a surprising way to protect atomically-thin electronics – adding vibrations, to reduce vibrations.

By ‘squeezing’ a thin droplet of liquid gallium, graphene devices are painted with a protective coating of glass, gallium-oxide. This oxide is remarkably thin, less than 100 atoms, yet covers centimeter-wide scales, making it potentially applicable for industrial large-scale fabrication.

Researchers from China's Hebei University of Technology and The Pennsylvania State University in the U.S have combined MXenes and laser-induced graphene foam nanocomposite to improve the design and performance of triboelectric nanogenerators (TENGs) - power sources that can be used for various flexible electronic devices and wearables.

The popularity of wearable electronics has induced demand for their parts, including power sources such as TENGs. Such power sources must be both stretchy and high-performance, holding up under various deformation conditions over hours of use. The researchers created a material system that enables a TENG to be stretchy and able to perform on dynamic surfaces, such as the human skin or the leaf of a plant. 

Researchers from the Chinese Academy of Sciences, the University of Science and Technology of China and North China University of Water Resources and Electric Power have studied the effects of irradiation defects on the work function of graphene electrodes in thermionic energy converters (TECs) and found that the generation of defects in graphene through irradiation would increase the work function and reduce the electron emission capacity.

Schematic diagram of a thermionic energy converter. (Image by ZHAO Ming) 

Graphene has great potential as an electrode coating material for TECs of the microreactor, which can significantly improve the electron emission ability of electrode. Electrode materials will be exposed to irradiation by high-energy particles during TECs use. Previous studies have shown that the types of defects induced by irradiation in graphene are mainly Stone-Wales defects, doping defects, and carbon vacancies. The appearance of defects will affect the adsorption properties of alkali and alkaline earth metals on the graphene surface in the electrode gap, and then change the electron emission properties of the graphene coating.

Skoltech researchers have patented a method that enables producing arbitrarily shaped functional graphene components on a transparent substrate with 100-nanometer resolution, which could be especially suited for flexible and transparent electronics. The new approach reportedly helps avoid defects that arise during graphene transfer between substrates and strongly affect the material’s quality.

“Flexible and transparent electronics is typically associated with wearable biosensors that monitor vital signs, such as heart rate, breathing, and blood oxygenation, and relay them to a smartphone or fitness band,” Skoltech PhD student Aleksei Shiverskii, one of the inventors, said. “An affordable and efficient technology that at first may seem impractical soon becomes a ubiquitous and indispensable appliance, like a bluetooth electric kettle or a wifi vacuum cleaner. I believe that someday flexible and transparent electronics will become a fixture, too.”

Scientists from Israel's Weizmann Institute of Science, in collaboration with teams at Manchester University and UC Irvine,  have shown that an electronic fluid can flow through materials without any electrical resistance, thereby perfectly eliminating a fundamental source of resistance that forms the ultimate limit for ballistic electrons. This result could open the door to improved electronic devices that do not heat up as much as existing technologies.

When electrons flow in electrical wires, they lose part of their energy, which is wasted as heat. This heating is a major problem in everyday electronics. The heating occurs because electrical conductors are never perfect and have a resistance for the flow of electrical currents. Typically, this resistance originates from the scattering of the flowing electrons by imperfections in the host material. But it stands to reason that a perfect conductor, devoid of any imperfections, would have zero resistance. However, even if the conductor is perfectly clean and free from imperfections, the resistance does not vanish. Instead, a new source of resistance emerges, known as the Landauer-Sharvin resistance. In an electrical conductor, electrons flow in quantum channels, much like cars in highway lanes. Similar to highway lanes, each electronic channel has a finite capacity to conduct electrons, limited by the quantum of conductance. For a given conductor, the number of quantum channels is finite and determined by its physical width. Thus, even a perfect electronic device, devoid of any imperfections, will never have infinite conductance. It will always have resistance. In the absence of interactions between electrons, this Landauer-Sharvin resistance is unavoidable, putting a fundamental lower bound on the heating of computer chips, which becomes even more severe as transistors become smaller.

Electronics and computer giant Dell has patented the design of a graphene-enhanced detachable clip for laptop computers, meant for wireless charging.

The clip uses a printed graphene charging coil built with a ferrite sheet as well as magnetic elements to hold the clip in place. This reportedly avoids increasing the size and thickness of the laptop. When the clip is installed on the laptop, charging circuitry is configured to supply inductive power to charge an auxiliary device such as a smartphone.