A group of researchers at the Siberian Federal University (SibFU) collaborated with foreign colleagues to elucidate the physical and structural properties of a class of two-dimensional materials based on polycyclic molecules known as circulenes.
The probability of variable properties and flexible design of these materials render them appropriate for nanoelectronics. The outcomes of the study have been reported in the Journal of Physical Chemistry C.
Circulenes are organic molecules containing a number of hydrocarbon cycles that form a flower-like structure. Their symmetricity, high stability, and optical properties render them of particular interest for nanoelectronics, specifically for organic LEDs and solar cells. The most studied and most stable tetraoxacirculene molecule could be potentially polymerized into graphene-like sheets and nanoribbons. The researchers have reported the results of simulations proving this probability. They also described the structure and properties of the proposed materials.
“Having only one building block—a tetraoxacirculene molecule—one can create a material with properties similar to those of silicon (a semiconductor traditionally used in electronics) or graphene (a semimetal) depending on the synthesis parameters. However, the proposed materials have some advantages. The charge carrier mobility is about 10 times higher compared to silicon, therefore, one could expect higher conductivity,” stated Artem Kuklin, the main author of the study and research associate at the department of theoretical physics of Siberian Federal University.
After finding out the equilibrium geometries and investigating their stability, the researchers discovered various stable tetraoxacirculene-based polymers. The difference between them was mainly due to the type of coupling between the molecules leading to distinctive properties. The polymers exhibit high charge carrier mobility. This characteristic was investigated by fitting energy zones near bandgap—a parameter represented by separation of occupied and empty electronic states. The mechanical properties indicate that the stretchability of the new materials is 1.5 to 3 times more than that of graphene. The authors also reiterated the presence of topological states in one of the polymers as a result of spin-orbit coupling, which is not usual for light elements-based materials. The materials that have such properties are insulators in the bulk; however, they can conduct electricity on the surface (edges).
The proposed nanostructures possess useful properties and may be used in various fields, from the production of ionic sieves to elements of nanoelectronic devices. Further we plan to develop this topic and modify our compounds with metal adatoms to study their magnetic and catalytic properties. We would also like to find a research group that could synthesize these materials.
Artem Kuklin, Research Associate, Department of Theoretical Physics, Siberian Federal University.