2D materials - Page 4

Researchers from MIT created a new 2D material, called 2DPA-1, which is the world's first 2D polymer. Until now, it was actually believed to be impossible to induce polymers into a 2D sheet.

To create the material, the researchers used a novel polymerization process, that was used to generate a two-dimensional sheet called a polyaramide. For the monomer building blocks of the material, they use a compound called melamine, which contains a ring of carbon and nitrogen atoms. Under the right conditions, these monomers can grow in two dimensions, forming disks. These disks stack on top of each other, held together by hydrogen bonds between the layers, which make the structure very stable and strong.

Researchers at the University of Vienna, in collaboration with the Universities of Tübingen, Antwerp and CY Cergy Paris and working with Danubia NanoTech, have developed a graphene-based method to produce 2D materials. They have already produced a new 2D material made of copper and iodine atoms sandwiched between two graphene sheets.

A single layer of cuprous iodide encapsulated in between two sheets of graphene (gray atoms). Image from Phys.org, credit: Kimmo Mustonen, Christoph Hofer and Viera Skákalov

Following the 2D copper iodide, the researchers have already expanded the synthesis method to produce other new 2D materials. "The method seems to be truly universal, providing access to dozens of new 2D materials. These are truly exciting times," Kimmo Mustonen, the lead author of the study, said.

Recent research has shown that the incorporation of graphene-related materials improves the performance and stability of perovskite solar cells. Graphene is hydrophobic, which can enhance several properties of perovskite solar cells. Firstly, it can enhance stability and the passivation of electron traps at the perovskite’s crystalline domain interfaces. Graphene can also provide better energy level alignment, leading to more efficient devices.

In a recent study, Spain-based scientists used pristine graphene to improve the properties of MAPbI₃, a popular perovskite material. Pristine graphene was combined with the metal halide perovskite to form the active layer of the solar cells. By analyzing the resulting graphene/perovskite material, it was observed that an average efficiency value of 15% under high-stress conditions was achieved when the optimal amount of graphene was used.

Researchers from Columbia University and collaborators from Korea's Sungkyunkwan University and Japan's National Institute for Materials Science have reported that graphene can be efficiently doped using a monolayer of tungsten oxyselenide (TOS) that is created by oxidizing a monolayer of tungsten diselenide.

The new results relied on a cleaner technique to manipulate the flow of electricity, giving graphene greater conductivity than metals such as copper and gold, and raising its potential for use in telecommunications systems and quantum computers.

Scientists studying two different configurations of bilayer graphene have detected electronic and optical interlayer resonances. In these resonant states, electrons bounce back and forth between the two atomic planes in the 2-D interface at the same frequency. By characterizing these states, they found that twisting one of the graphene layers by 30 degrees relative to the other, instead of stacking the layers directly on top of each other, shifts the resonance to a lower energy. From this result they deduced that the distance between the two layers increased significantly in the twisted configuration, compared to the stacked one. When this distance changes, so do the interlayer interactions, influencing how electrons move in the bilayer system. An understanding of this electron motion could inform the design of future quantum technologies for more powerful computing and more secure communication.

Today’s computer chips are based on our knowledge of how electrons move in semiconductors, specifically silicon, said first and co-corresponding author Zhongwei Dai, a postdoc in the Interface Science and Catalysis Group at the Center for Functional Nanomaterials (CFN) at the U.S. Department of Energy (DOE)’s Brookhaven National Laboratory. But the physical properties of silicon are reaching a physical limit in terms of how small transistors can be made and how many can fit on a chip. If we can understand how electrons move at the small scale of a few nanometers in the reduced dimensions of 2-D materials, we may be able to unlock another way to utilize electrons for quantum information science.

Scientists at Tohoku University and colleagues in Japan have developed a mathematical model that abstracts the key effects of changes to the geometries of carbon material and predicts its unique properties.

Scientists generally use mathematical models to predict the properties that might emerge when a material is changed in certain ways. Changing the geometry of three-dimensional (3D) graphene, which is made of networks of carbon atoms, by adding chemicals or introducing topological defects, can improve its catalytic properties, for example. But it has been difficult for scientists to understand why this happens exactly.

A research team at Nagoya University in Japan has developed a new technique for synthesizing nanographenes, remarkable materials with a vast number of potential structures that can even exhibit electric and magnetic characteristics beyond those of graphene.

Since each nanographene exhibits different physical characteristics, the key to applied nanographene study is to determine the relationship between the structure and characteristics of as many nanographenes as possible.

Gnanomat recently announced the launch of its new commercially-available graphene-based nanocomposite.

Graphene Silver nanocomposite, a product supplied as a dry powder, is made of pristine graphene coated with silver nanoparticles. This type of material has been shown to have great potential in scientific literature, in applications such as inks on textiles for highly conductive wearable electronics, electrochemical sensors, catalyst, antibacterial activity and detection of heavy metal ions.

Researchers from the Department of Physics and the Swiss Nanoscience Institute at the University of Basel, working in collaboration with the University of Bern, have recently produced and studied a compound referred to as "kagome graphene", that consists of a regular pattern of hexagons and equilateral triangles that surround one another. The name kagome comes from the old Japanese art of kagome weaving, in which baskets are woven in the same pattern.

Kagome graphene is characterized by a regular lattice of hexagons and triangles. Credit: R. Pawlak, Department of Physics, University of Basel

The team's measurements have reportedly delivered promising results that point to unusual electrical or magnetic properties of the material.

Researchers affiliated with the Graphene Flagship from RWTH Aachen University, Universität der Bundeswehr München and AMO in Germany, KTH Royal Institute of Technology in Sweden and with Protemics have reported a new method to integrate graphene and 2D materials into semiconductor manufacturing lines, a milestone for the recently launched 2D-EPL project.

Image from Nature Communications

Two-dimensional (2D) materials have a huge potential for providing devices with much smaller size and extended functionalities with respect to what can be achieved with today's silicon technologies. But to exploit this potential, it is vital to be able to integrate 2D materials into semiconductor manufacturing lines - a notoriously difficult step. This new technique could be a step in the right direction as far as solving this problem is concerned.