Technical / Research

Researchers explore the superconducting limit of ‘magic angle’ graphene

When two sheets of are stacked together and offset at a slight angle, the bilayer material can produce numerous intriguing effects, notably superconductivity. Cornell University researchers have gained new understanding on how twisted bilayer graphene achieves this state, by identifying its highest achievable superconducting temperature – 60 Kelvin. The finding is said to be mathematically exact, a rare feat in the field, and is spurring new insights into the factors that fundamentally control superconductivity. 

“Looking ahead, this paves the way for understanding what are the possible degrees of freedom that one should try to control and optimize in order to enhance the tendency towards superconductivity in these two-dimensional material platforms,” said Debanjan Chowdhury, who co-authored the recent study.

Read the full story Posted: Nov 07,2024

Novel graphene-based sensor system rapidly detects toxic gas

Researchers at the University of Virginia, Ajou University and Soongsil University have developed an AI-powered system that mimics the human sense of smell to detect and track toxic gases in real time. Using advanced artificial neural networks combined with a network of sensors, the system quickly identifies the source of harmful gases like nitrogen dioxide (NO₂) that poses severe respiratory health risks.

Schematic of biological and artificial olfactory receptor. Biological receptors interact with odor molecules through specific binding, whereas artificial receptors use catalytic dissociation by Pd nano-islands for selective gas molecule adsorption on graphene surfaces. Image credit: Science Advances

The artificial olfactory receptor features nano-islands of metal-based catalysts that cover a graphene surface on the heterostructure of an AlGaN/GaN two-dimensional electron gas (2DEG) channel. Catalytically dissociated NO2 molecules bind to graphene, thereby modulating the conductivity of the 2DEG channel and allowing the system to detect gas leaks with extreme sensitivity.

Read the full story Posted: Oct 30,2024

Researchers develop GrapheNet: a deep learning framework for predicting the physical and electronic properties of nanographenes using images

Researchers from ISMN-CNR have introduced GrapheNet, a deep learning framework based on an Inception-Resnet architecture using image-like encoding of structural features for the prediction of the properties of nanographenes.

Scheme of the GrapheNet framework. Image from Scientific Reports

By exploiting the planarity of quasi-bidimensional systems and through encoding structures into images, and leveraging the flexibility and power of deep learning in image processing, Graphenet is said to achieve significant accuracy in predicting the physicochemical properties of nanographenes. 

Read the full story Posted: Oct 19,2024

Novel plasma-based method increases graphene production by more than 22%

A research team from the University of Córdoba (UCO) has developed a new prototype that could lead opens the door to the large-scale production of graphene. This new method, which has already been registered for evaluation as a patent and is based on a previous patent by the same team, increases the production of graphene by more than 22%, with the process maintaining the high quality that characterizes graphene synthesized with this technology.

The work is based on plasma technology, a partially ionized gas often referred to as the fourth state of matter. One of its great advantages, highlighted the study's lead author, Francisco Javier Morales, is that "it is a highly energetic medium that is capable of breaking down organic molecules very easily." Specifically, the team used this plasma torch to break down ethanol and rearrange the molecule's carbon atoms, resulting in the creation of graphene.

Read the full story Posted: Oct 12,2024

Researchers investigate the ultrafast opto-electronic and thermal tuning of nonlinear optics in graphene

An international group of scientists, including ones from the UK's University of Bath, Friedrich Schiller University Jena in Germany and the University of Pisa in Italy, recently set out to investigate the ultrafast opto-electronic and thermal tuning of nonlinear optics in graphene.

Opto-electronic modulation of third harmonic generation in a graphene field-effect transistor. The illustration includes a sketch and a microscopic optical image of the device. Image credit: University of Bath

Nonlinear optics explores how powerful light (e.g. lasers) interacts with materials, resulting in the output light changing color (i.e. frequency) or behaving differently based on the intensity of the incoming light. This field is important for developing advanced technologies such as high-speed communication systems and laser-based applications. Nonlinear optical phenomena enable the manipulation of light in novel ways, leading to breakthroughs in fields like telecommunications, medical imaging, and quantum computing. Graphene's exceptional electronic properties, related to relativistic-like Dirac electrons and strong light-matter interactions, make it promising for nonlinear optical applications, including ultrafast photonics, optical modulators, saturable absorbers in ultrafast lasers, and quantum optics.

Read the full story Posted: Oct 09,2024

Researchers design graphene-based RF NEMS switches with excellent performance

Researchers from the Taiyuan Institute of Technology have introduced a novel graphene RF NEMS capacitive switch and conducted an extensive analysis of its RF performance within the UWB frequency range of DC ~ 140 GHz. 

Schematic representation of the proposed graphene RF NEMS capacitive switch: (a) a 3D isometric view; (b) a top view. Image credit: Scientific Reports

The monolayer graphene RF NEMS switch is characterized by its low pull-in voltage, rapid switching time, and superior RF performance, contrasting with the comparatively inferior performance of multilayer graphene RF NEMS switches. 

Read the full story Posted: Oct 08,2024

New platform allows scientists to study materials at the level of individual molecules

University of Illinois Chicago scientists have created a new platform to study materials at the level of individual molecules. The approach is a significant breakthrough for creating nanotechnologies that could revolutionize computing, energy and other fields.

Two-dimensional materials, such as graphene, are made from a single layer of atoms. Studying and designing these ultrathin materials requires highly specialized methods. The laboratory of Nan Jiang, associate professor of chemistry and physics at UIC, pioneered a new method to simultaneously examine the structural, electronic and chemical properties of these nanomaterials. The platform combines two scientific approaches — scanning probe microscopy and optical spectroscopy — to view materials and assess how they interact with chemicals.

Read the full story Posted: Sep 21,2024

Researchers combine graphene and silk for advanced microelectronics, wearables and next-gen computing applications

While silk protein has been used in designer electronics, its use is currently limited in part because silk fibers are a messy tangle of spaghetti-like strands. To address this, researchers from Pacific Northwest National Laboratory, University of Washington, Lawrence Berkeley National Laboratory, North Carolina State University and Xiamen University have developed a uniform two-dimensional (2D) layer of silk protein fragments, or "fibroins," on graphene. 

Scheme of silk fibroin assembly on highly oriented pyrolytic graphite (HOPG) characterized by in situ AFM. Image from Science Advances

The scientists explained that their work provides a reproducible method for silk protein self-assembly that is essential for designing and fabricating silk-based electronics. They said that the system is nontoxic and water-based, which is vital for biocompatibility.

Read the full story Posted: Sep 19,2024

Researchers develop improved hydrogen ion barrier films using pore-free graphene oxide membranes

Researchers from Kumamoto University and Hiroshima University have announced a significant development in hydrogen ion barrier films using graphene oxide (GO) without internal pores. This approach could be beneficial for protective coatings for various applications.

In their study, the research team successfully synthesized and developed a pore-free GO (Pf-GO) membrane with controlled oxygen functional groups. Traditionally, GO has been known for its high ionic conductivity, which made it challenging to use as an ion barrier. However, by eliminating the internal pores, the team created a material with dramatically improved hydrogen ion barrier properties.

Read the full story Posted: Sep 15,2024

Researchers develop a graphene-based wearable strain sensor that can detect and broadcast silent speech

Researchers from the University of Cambridge, University College London, Imperial College London, Kumoh National Institute of Technology (KIT) and Beihang University have developed a wearable ‘smart’ choker for speech recognition, that has the potential to redefine the field of silent speech interface (SSI) thanks to embedded ultrasensitive textile strain sensor technology.

Where verbal communication is hindered, such as in locations with lots of background noise or where an individual has an existing speech impairment, SSI systems are a cutting-edge solution, enabling verbal communication without vocalization. As such, it is a type of electronic lip-reading using human-computer interaction. In their recent research, the scientists applied an overlying structured graphene layer to an integrated textile strain sensor for robust speech recognition performance, even in noisy environments.

Read the full story Posted: Sep 10,2024