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From graphene towards new wonder materials

Graphene, a single layer of carbon atoms, is often called the wonder material of the millennium. The next development step is ‘molecular graphene,’ whose properties TUT’s researchers examined in an article published in the renowned Nano Letters science journal.

Graphene has truly earned its reputation as a wonder material: it is a hundred times stronger than steel, it conducts heat and electricity better than almost any other material, it is 98% transparent, and it can be reshaped to form carbon nanotubes, for example.

“Recently, attention has been attracted by so-called artificial graphene, in which individual molecules are positioned on a metal surface so that the electrons in the metal move in a honeycomb-like pattern similar to graphene. This way, many of the favourable properties of graphene can be transferred to other materials and the electric conductance can be manipulated as needed,” Professor Esa Räsänen from TUT’s Department of Physics explains.

The study showed that a pattern of carbon monoxide molecules on top of a copper surface locally possesses graphene-like properties. The conductance can be further manipulated by changing the positions of the molecules on the surface. These results partly confirm the previous experiments carried out at Stanford University. On the other hand, the results show that electrons in ‘molecular graphene’ behave in a surprising way: they are simultaneously localized in two completely different honeycomb structures.

“With these new results, we have a better understanding of the behaviour of electrons in graphenes and graphene-like structures. In the long run, this knowledge will guide us in the design of novel ultrathin materials that can be applied as nanoscale transistors, for example,” Räsänen says.

The research was carried out in the computational physics group at TUT’s Department of Physics by University Teacher Sami Paavilainen, Postdoctoral Researcher Matti Ropo, University Lecturer Jouko Nieminen and Professors Jaakko Akola and Esa Räsänen. The study is a part of Professor Räsänen’s Science of Designer Electrons Academy of Finland project and it also belongs to Professor Akola’s activities at the Centre of Excellence in Computational Nanoscience research (COMP).

The work was published in the renowned peer-reviewed Nano Letters science journal in May 2016.

Further information from the researchers at TUT’s Department of Physics:
Professor Esa Räsänen, tel. +358 (0) 50 301 3386,
University Teacher Sami Paavilainen, tel. +358 (0) 40 849 0366,
Professor Jaakko Akola, tel. +358 (0) 40 198 1179,

News submitted by: Tiina Leivo
Keywords: science and research, graphene