Technical / Research

Researchers develop graphene-enabled single fiber actuator inspired by human muscles

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) and Pusan National University in South Korea recently developed a graphene-enhanced  actuator for robotics applications, that is inspired by mammalian skeletal and muscle structures. The new actuator is based on soft fibers with strong contractive actuation properties.

The team explained that they based their work on liquid crystal elastomer (LCE) actuators, promising soft actuator materials with unusually large reversible dimensional change (shrink/relaxation) upon actuation, which is rarely observed in other kinds of actuator materials but highly significant to ideally mimic natural skeletal muscle behavior. Many actuators developed in the past are based on LCE materials, a class of polymers that can rapidly change shape in response to environmental stimuli. Despite their shape-morphing advantages, LCE polymers are known to be associated with the relatively poor mechanical properties and weak actuation behavior. To overcome this limitation, the researchers incorporated graphene fillers within the LCE actuators. In addition to enhancing their mechanical properties, the team expected the graphene fillers to enable light-driven, rapid and remotely controllable actuation, owing to the photothermal conversion capability of graphene.

Read the full story Posted: Nov 26,2022

Researchers study the effects of defects on electron emission of Graphene electrodes

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.

Read the full story Posted: Nov 24,2022

Researchers achieve water-enabled electricity generation through highly oriented graphene oxide nanochannels

Researchers from China's Tsinghua University have constructed highly aligned graphene oxide (GO) nanochannels for sustainable energy production using a freeze-casting process. The new method could address an issue that impedes the generation of electricity from natural water flow through engineered nanochannels, which could become a viable way to cater to the fast-growing renewable power needs.

Large-scale nanochannel integration and the multi-parameter coupling restrictive influence on electric generation currently remain big challenges for macroscale applications, but this novel design encourages spontaneous absorption and directed transfer of water within the nanochannels to generate clean electricity.

Read the full story Posted: Nov 23,2022

Skoltech team patents method for defect-free graphene for flexible transparent electronics

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.”

Read the full story Posted: Nov 22,2022

Researchers turn waste byproduct asphaltene into graphene

Researchers from Rice University, University of Calgary, South Dakota School of Mines and Technology and University of Washington have managed to turn a waste material called asphaltene (a byproduct of crude oil production) into graphene.

Rice University's Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is employing Rice’s unique flash Joule heating process to convert asphaltenes instantly into turbostratic (loosely aligned) graphene and mix it into composites for thermal, anti-corrosion and 3D-printing applications. The process makes good use of material otherwise burned for reuse as fuel or discarded into tailing ponds and landfills. Using at least some of the world’s reserve of more than 1 trillion barrels of asphaltene as a feedstock for graphene would be good for the environment as well.

Read the full story Posted: Nov 19,2022

Researchers use graphene to measure the properties of a material’s surface layer

Researchers from Northeastern University in Boston and University of Texas at Arlington (UTA) have used a process called auger-mediated positron sticking (AMPS) to  develop a new technique that can measure the properties of the topmost atomic layer of materials.

This spectroscopic tool uses virtual photons to measure the topmost atomic layer’s electronic structure selectively. When incoming positrons change from vacuum states to bound surface states on the sample surface, they produce virtual photons with the energy to excite electrons into the vacuum.

Read the full story Posted: Nov 15,2022

Researchers create tunable monolithic SQUID component based on twisted bilayer graphene

Researchers from Switzerland's ETH Zurich and Japan's National Institute for Materials Science (NIMS) have produced the first superconducting quantum interference device, or SQUID, from twisted graphene for the purpose of demonstrating the interference of superconducting quasiparticles. This work is based on former research in which, about a year ago, a team of researchers led by Klaus Ensslin and Thomas Ihn at ETH Zurich's Laboratory for Solid State Physics was able to demonstrate that twisted graphene could be used to create Josephson junctions, the fundamental building blocks of superconducting devices.

Conventional SQUIDs are already being used, for instance in medicine, geology and archaeology. Their sensitive sensors are capable of measuring even the smallest changes in magnetic fields. However, SQUIDs work only in conjunction with superconducting materials, so they require cooling with liquid helium or nitrogen when in operation. In quantum technology, SQUIDs can host quantum bits (qubits); that is, as elements for carrying out quantum operations. "SQUIDs are to superconductivity what transistors are to semiconductor technology—the fundamental building blocks for more complex circuits," Ensslin explains.

Read the full story Posted: Nov 04,2022

Researchers design impressive all-in-one miniature spectrometers using graphene and Mos2

An international team of researchers, including ones from Aalto University, Shanghai Jiao Tong University, Zhejiang University, Sichuan University,  Oregon State University, Yonsei University and the University of Cambridge, have designed a miniaturized spectrometer made of a ‘sandwich’ of different ingredients, including graphene, molybdenum disulfide, and tungsten diselenide. 

The spectrometer reportedly breaks all current resolution records, and does so in a much smaller package, thanks to computational programs and artificial intelligence. The new miniaturized devices could be used in a broad range of sectors, from checking the quality of food to analyzing starlight or detecting faint clues of life in outer space.

Read the full story Posted: Oct 22,2022

Researchers use graphene oxide to create a self-powered sensor that translates sign language into audio

Researchers from Tsinghua University recently developed a self-powered sensor that can monitor and detect multiple environmental stimuli simultaneously and demonstrated how it can “translate” sign language into audio.

The sensor was made from graphene oxide and powered internally by a moist electric generator called MEG, which contains a membrane that spontaneously absorbs water from the air. When water adheres to the surface, this results in a higher concentration of hydrogen ions at the top of the membrane and a potential difference between its two electrodes.

Read the full story Posted: Oct 20,2022

Graphene assists researchers to develop a novel nondestructive imaging platform

Researchers from Lawrence Berkeley National Laboratory and University of California at Berkeley recently used graphene to develop an imaging platform that enabled nondestructive spectroscopic imaging of soft materials with nanometer spatial resolution, under in vitro conditions and external stimuli. Using the Advanced Light Source (ALS) particle accelerator as an infrared light source, the researchers performed the nanometer-scale spatial resolution imaging of proteins in the proteins’ natural liquid environment. They observed how the self-assembly of the proteins was affected by environmental conditions in the surrounding liquid.

Current imaging tools often use ionizing radiation under conditions that are far from the molecule’s native biological environment. Powerful imaging techniques such as fluorescence microscopy can potentially damage biological material, and they often do not provide chemical information. To resolve this challenge, the researchers combined nano-Fourier transform infrared (nano-FTIR) spectroscopy with graphene-capped liquid cells. The imaging platform could open opportunities in the study of soft materials for sectors that range from biology to plastics processing to energy.

Read the full story Posted: Oct 19,2022