Technical / Research

Researchers develop deformable graphene-based liquid metal micro-supercapacitors

Researchers from Pohang University of Science and Technology (POSTECH), Korea Institute of Industrial Technology and Konkuk University have fabricated highly deformable graphene-based micro supercapacitors (MSCs) using liquid metal current collectors on an elastic polymer substrate.

a Illustration of an integrated system comprising soft-electronics and deformable energy storage component. b The fabrication process of EGaIn-based MSC. c UV-vis spectra of SEBS, EGaIn, and graphene. FE-SEM images of laser ablated d Graphene/EGaIn and e EGaIn (Scale bar = 200 µm). Photographs of f institute logos, g deformed logos, and h an LED connected to the MSC circuit (Scale bar = 1 cm). (Image from npj Flexible Electronics)

The team used eutectic gallium-indium (EGaIn), a liquid metal alloy, as the current collector since a deformable current collector is needed in order to create a deformable MSC. Commonly used current collectors made of brittle materials like gold (Au) are not suitable in this case, so the team turned to 'liquid metal' that inherently possesses the properties of a liquid and metallic conductivity.

Read the full story Posted: Mar 18,2024

Researchers develop diamond/graphene composite with high electrical conductivity and hardness

Researchers from China's Zhengzhou University, Ningbo University and Jilin University have used nanodiamonds as precursors to make centimeter-sized diamond/graphene composites under moderate pressure and temperature conditions (12 GPa and 1,300 to 1,500 °C). The composite is reportedly able to conduct electricity while maintaining its ultra-hardness.

This work could pave the way for realizing large-sized diamond-based materials with ultrahigh electrical conductivity and superior mechanical properties under moderate synthesis conditions, which will facilitate their large-scale applications in a variety of fields.

Read the full story Posted: Mar 10,2024

Research develop new non-toxic method for producing high-quality graphene oxide

Researchers at Sweden's Umeå University, Lund University and Denmark's Aarhus University have reported a new way to synthesize graphene oxide, which has significantly fewer defects compared to materials produced by the most common method. To date, graphene oxide of similarly good quality could only be synthesized by using a rather dangerous method involving extremely toxic fuming nitric acid.

Graphene oxide is often used to produce graphene by removing oxygen. However, if there are holes in graphene oxide, there will also be holes after it is converted to graphene. Therefore, the quality of the graphene oxide is very important. Umeå University's Alexandr Talyzin and his research group have now addressed the issue of how to safely make good graphene oxide. 

Read the full story Posted: Feb 21,2024

Researchers shed light on electron-phonon interactions using 'magic angle' graphene

Researchers from ICN2, ICFO, Tokyo Institute of Technology, TU Eindhoven, National Institute for Material Sciences, MIT and Ludwig Maximilian University have studied electron-phonon interactions and found a remarkable speedup in cooling of twisted bilayer graphene near the 'magic angle': The cooling time is a few picoseconds from room temperature down to 5 kelvin, whereas in pristine bilayer graphene, cooling to phonons becomes much slower for lower temperatures. 

“We sought to understand how electrons and phonons ‘talk’ to each other within two twisted graphene layers,” says Klaas-Jan Tielrooij, associate professor at the Department of Applied Physics and Science Education at TU/e and the research lead of the new work.

Read the full story Posted: Feb 13,2024

Researchers develop adhesive tape that can transfer 2D materials like graphene in an easier, cheaper and less-damaging way

Researchers from Kyushu University, Nitto Denko Corporation, Tokyo Institute of Technology, Osaka University, National Institute of Advanced Industrial Science and Technology (AIST) and Samsung Electronics have developed a tape that can be used to stick 2D materials to many different surfaces, in an easy and user-friendly way. 

Transfer process of monolayer graphene from Cu(111)/sapphire to a SiO2/Si substrate using the UV tape. Image from Nature Electronics

“Transferring 2D materials is typically a very technical and complex process; the material can easily tear, or become contaminated, which significantly degrades its unique properties,” says lead author, Professor Hiroki Ago of Kyushu University's Global Innovation Center. “Our tape offers a quick and simple alternative, and reduces damage.”

Read the full story Posted: Feb 12,2024

Researchers use graphene to develop new metasurface architectures for ultrafast information processing and versatile terahertz sources

Traditional microelectronic architectures are currently used to power everything from advanced computers to everyday devices. However, scientists are always on the lookout for better technologies. Recently, Los Alamos National Laboratory scientists and their collaborators from Menlo Systems and Sandia National Laboratories, have designed and fabricated asymmetric, nano-sized gold structures on an atomically thin layer of graphene. The gold structures are dubbed “nanoantennas” based on the way they capture and focus light waves, forming optical “hot spots” that excite the electrons within the graphene. Only the graphene electrons very near the hot spots are excited, with the rest of the graphene remaining much less excited.

Illustration of an optoelectronic metasurface consisting of symmetry-broken gold nanoantennas on graphene. Image from Nature

The team adopted a teardrop shape of gold nanoantennas, where the breaking of inversion symmetry defines a directionality along the structure. The hot spots are located only at the sharp tips of the nanoantennas, leading to a pathway on which the excited hot electrons flow with net directionality — a charge current, controllable and tunable at the nanometer scale by exciting different combinations of hot spots. 

Read the full story Posted: Feb 08,2024

Researchers design artificial neuron based on graphene and water

Researchers from Germany's Max Planck Institute for Polymer Research and China's Southeast University have reported a graphene-based aqueous memristive device with long-term and tunable memory, regulated by reversible voltage-induced interfacial acid-base equilibria enabled by selective proton permeation through the graphene. 

Memristive devices, electrical elements whose resistance depends on the history of applied electrical signals, are leading candidates for future data storage and neuromorphic computing. Memristive devices typically rely on solid-state technology, while aqueous memristive devices are crucial for biology-related applications such as next-generation brain-machine interfaces. Recently, nanofluidic devices have been reported in which solvated ion transport exhibits memristive behavior. The challenge associated with these approaches is the complexity of the device fabrication. Realizing memristive behavior in a simple system is highly desirable.

Read the full story Posted: Feb 07,2024

Researchers develop ultra-sensitive graphene-based lead detector

Scientists at the University of California San Diego have developed an ultra-sensitive graphene-based sensor that can detect extraordinarily low concentrations of lead ions in water. The device achieved a record limit of detection of lead down to the femtomolar range, which is said to be a million times more sensitive than previous sensing technologies.

The device in this study consisted of a single layer of graphene mounted on a silicon wafer. The researchers enhanced the sensing capabilities of the graphene layer by attaching a linker molecule to its surface. This linker serves as the anchor for an ion receptor and, ultimately, the lead ions.

Read the full story Posted: Feb 06,2024

Rice researchers map the diffusion of graphene and hexagonal boron nitride in aqueous solutions

Rice University researchers have mapped out how bits of 2D materials move in liquid ⎯ which that could help scientists assemble macroscopic-scale materials with the same useful properties as their 2D counterparts.

In order to maintain these special properties in bulk form, sheets of 2D materials have to be properly aligned ⎯ a process that often occurs in solution phase. The Rice team focused on graphene and hexagonal boron nitride, a material with a similar structure to graphene but composed of boron and nitrogen atoms.

Read the full story Posted: Feb 04,2024

Researchers design copper-graphene composites with improved electrical conductivity

Researchers from North Carolina State University and Pacific Northwest National Laboratory (PNNL) recently used shear assisted processing and extrusion (ShAPE) to synthesize macro-scale copper-graphene composites with a simultaneously lower temperature coefficient of resistance (TCR) and improved electrical conductivity over copper-only samples. 

The team's new graphene-copper composite with an improved ability to conduct electricity could lead to more efficient electricity distribution to homes and businesses, as well as more efficient motors to power electric vehicles and industrial equipment. The team has applied for a patent for the work, which was supported by the Department of Energy (DOE) Advanced Materials and Manufacturing Technologies Office.

Read the full story Posted: Feb 02,2024