Photo: Bax LIndhardt

Young chemist behind new 2D material

Tuesday 19 Feb 19
by Morten Andersen


Kasper Steen Pedersen
Assistant Professor
DTU Chemistry
+45 23 60 40 67
International research team headed by young chemist designs a new 2D material by combining organic molecules through inorganic ions.

A group of international researchers led by 32-year-old Assistant Professor Kasper Steen Pedersen of DTU Chemistry has created a new 2D material through chemical synthesis.

The new material has special electrical and magnetic properties that make it useful in the quantum computers of tomorrow and other electronics.

CrCI2(pyrazine)2 is a layered material and the precursor for the so-called 2D materials.

2D materials that, in principle, have a thickness corresponding to that of only a single molecule, often have completely different properties than a normal 3D version of the same material. Especially when it comes to the electrical properties. 

In 3D material, the electrons are free to move in all directions. However, as long as the wavelength of the electrons is longer than the thickness of the 2D material, they will be forced to move horizontally.

Chemical design of the material

The new material differs significantly from graphene and the other known inorganic 2D materials. Unlike these, CrCI2(pyrazine)2 is a compound of organic and inorganic material.

Photo: Bax Lindhardt

“This material is an example of a new form of chemistry in which we are able to change some of the building blocks of the material and thus modify its physical and chemical properties. This is not possible with graphene—you cannot, or example, choose to replace half of the atoms in the grid with something other than carbon. However, with our approach it is possible to design the properties of the material with far more accuracy than in other 2D materials,” says Kasper Steen Pedersen.

The new organic-inorganic compound has a high level of conductivity caused by the ability of the electrons to jump between the molecular building blocks through the material in two dimensions.

In addition to being able to very accurately design the electrical properties of CrCI2(pyrazine)2 very accurately, it is also possible to change the magnetic properties. This is particularly relevant for spintronics.

“In spintronics, we do not just use the charge of the electrons—as is the case in electronics— but also the spin, which is a property of quantum mechanics. This is particularly interesting to quantum computing. The development of nanoscale materials which are both conductive and magnetic is thus highly relevant,” says Kasper Steen Pedersen.

Can lead to more materials

CrCI2(pyrazine)2 is not only interesting for use in quantum computers, but also for future superconductors, catalysts, batteries, fuel cells, and electronics in general. The researcher emphasizes that there are not currently any companies that are eager to produce the material:

“We are still talking about basic research. We have created a material from an innovative concept, which is precisely why there are still many questions we need to answer. For example, we cannot yet how stable the material will be in various applications. Nevertheless, even if CrCI2(pyrazine)2 should prove to unsuitable for some reason, the new principles that we have applied could still be useful. We have opened up an entire new world of more advanced 2D materials.”

The successful production of the new 2D material was published in Nature Chemistry in September, 2018.

Illustration: DTU Chemistry
The figures show the atomic structure of CrCI2(pyrazine)2. The dark green ‘balls’ are chromium, the bright green ones chlorine, the blue ones nitrogen, and the dark grey ones are carbon. The material also contains hydrogen atoms, but they have been omitted for clarity. Figure A shows a section of the material along the chlorine-chrome chlorine axis b-a. Figure B shows the material in three dimensions, and the layered structure becomes clear. The observant reader will notice that the material is three-dimensional, but the researchers are well on their way to reducing the two layers to one, so that the material will become fully two-dimensional. 

About the new material

Photo: Bax Lindhardt

In a small test tube in one of DTU’s chemistry laboratories lies a brand new material, which does not naturally occur on Earth.

The material, which looks like coal dust, is created through chemical synthesis. An international research team connected molecular building blocks for the new material CrCI2(pyrazine)2, which is a compound of organic and inorganic material.

Researchers believe that a compound of organic materials such as pyrazine and magnetic ions such as chromium will generally be well-suited for the production of 2D materials with adjustable electric and magnetic properties.

On the international team are researchers from Université de Bordeaux, University of California, Berkeley, University of Oxford, University of Copenhagen, Aarhus University, and more.