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

Researchers use graphene FET biosensor for simultaneous detection of influenza and SARS-CoV-2

Researchers from University of Texas at Austin have developed an antibody (Ab)-modified graphene field effect transistor (GFET)-based biosensor for precise and rapid influenza A virus (IAV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protein detection and differentiation.

The sensor chip that was developed comprised of four GFETs in a quadruple arrangement, separated by polydimethylsiloxane (PDMS) enclosures. Every quarter was biochemically functionalized with SARS-CoV-2 and IAV antigen-targeted Abs, one chemically passivated control, and one bare control. The third (chemically passivated) GFET was deployed to ensure that the results observed were due to Ab-antigen interaction rather than electronic fluctuations or drifts.

Read the full story Posted: Oct 18,2022

Researchers develop method for the fabrication of mesoporous graphene for energy storage systems

Researchers from South-Korea's Pohang University of Science and Technology (POSTECH), Kumoh National Institute of Technology, Sungkyunkwan University, Yeungnam University, Konkuk University and University of Seoul have proposed a simple strategy for the fabrication of mesoporous graphene with applications in high-performance energy storage systems like electric double-layer supercapacitors (EDLCs).

Conventional energy storage systems made of activated carbons (ACs) tend to have a poor power density due to the insufficient specific contact area, leading to inadequate creation of an electric double layer between electrode material and electrolyte. Therefore, an active material with a high specific contact area could help obtain high energy densities and meet the needs of various energy storage systems. Graphene's remarkable electrical conductance naturally makes it a logical candidate, but the high van der Waals contact between the graphene sheets makes stacking unavoidable, producing a limited available surface area. 

Read the full story Posted: Oct 17,2022

Graphene help researchers to develop efficient oxygen catalysts for lithium-oxygen batteries

Researchers from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) and Henan Agricultural University have designed two-dimensional (2D) Mn3O4 nanosheets with dominant crystal planes on graphene (Mn3O4 NS/G) as efficient oxygen catalysts for Li-O2 batteries, achieving ultrahigh capacity and long-term stability.

The team explained that designing oxygen catalysts with well-defined shapes and high-activity crystal facets can effectively regulate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the three-phase interfaces, but it is still remains challenging. The researchers reported that the Mn3O4 NS/G with the (101) facets and enriched oxygen vacancies offered a lower charge overpotential of 0.86 V than that of Mn3O4 nanoparticles on graphene (1.15 V).

Read the full story Posted: Oct 17,2022

Researchers address the stability problems of graphene nanoribbon zigzag edges

An international team, including scientists from DIPC and CFM (CSIC-UPV/EHU) in San Sebastian, CIQUS - Universidade de Santiago de Compostela, Czech Academy of Sciences (Prague), Palacký University (Olomouc), Ikerbasque (Basque Country) and CINN (CSIC-UNIOVI-PA) in El Entrego, have demonstrated two chemical protection/deprotection strategies for the on-surface synthesis of graphene nanostructures.

On-surface synthesis is a synthetic approach that differs from standard wet-chemistry approaches. Instead of the three-dimensional space of solvents in the latter, the environment of the reactants in this approach are well-defined two-dimensional solid surfaces that are typically held under vacuum conditions. These differences have allowed the successful synthesis of a great variety of molecular structures that could not be obtained by conventional means. Among the structures that are raising particular interest are carbon-nanostructures with zigzag-shaped edges, which endow the materials with exciting electronic and even magnetic properties of potential interest for a great variety of applications that include quantum technologies.

Read the full story Posted: Oct 08,2022

Researchers use graphene electrodes to split water molecules

An international team of scientists, led by Dr. Marcelo Lozada-Hidalgo based at the National Graphene Institute (NGI), used graphene as an electrode to measure both the electrical force applied on water molecules and the rate at which these break in response to such force. The researchers found that water breaks exponentially faster in response to stronger electrical forces.

The researchers believe that this fundamental understanding of interfacial water could be used to design better catalysts to generate hydrogen fuel from water. Dr Marcelo Lozada-Hidalgo said: “We hope that the insights from this work will be of use to various communities, including physics, catalysis, and interfacial science and that it can help design better catalysts for green hydrogen production”.

Read the full story Posted: Oct 07,2022

Researchers realize zero-bias operation of a graphene photodetector

NTT Corporation and the National Institute for Materials Science (NIMS) have jointly reported the realization of what they define as "the world's fastest zero-bias operation (220 GHz) of a graphene photodetector (PD)". The research conducted by NTT and NIMS has also, according to the statement, clarified the optical-to-electrical (O-E) conversion process in graphene for the first time.

Graphene is a promising photodetection material for enabling high-speed O-E conversion at wavelength ranges where existing semiconductor devices cannot operate, thanks to its high sensitivity and high-speed electrical response to a wide range of electromagnetic waves, from terahertz (THz) to ultraviolet (UV). However, until now, the demonstrated zero-bias operating speed has been limited to 70 GHz due to conventional device structure and measurement equipment. For this reason, the challenge for graphene PDs is to demonstrate 200-GHz operation speeds and clarify graphene's inherent properties, such the process of optical-to-electrical conversion.

Read the full story Posted: Sep 28,2022