Both 2D and 3D supracrystals are theoretical materials that have yet to be synthesized. Despite this, scientists are working hard on the computational front to see what structures 2D supracrystals could form, what materials can be used, their potential properties and what applications they could be used in. In this article, we look at the work done to date to help realize supracrystals and their potential applications.
What are 2D Supracrystals?
2D supracrystals are theoretical materials. Lots of work has been done by computational scientist to try and predict the various possible structures and the associated properties. Supracrystals are long-range periodic crystals. 3D supracrystals have a periodic order in all three dimensions, but 2D supracrystals have a periodic order in two dimensions. A high molecular symmetry is one of the main factors that defines what a supracrystal is.
The high symmetry in supracrystals arises from the replacement of the atoms with their symmetric complex at the node points (corners) of a crystal lattice. For example, conventional graphene sheets have a regular array of hexagonal carbon atoms where a single atom is the node of the unit cell. Graphene-like supracrystals, on the other hand, would require either four or six carbons (atomic polygon) arranged as the node of the unit cell to create a symmetrical pattern. Many materials, including 2D carbon, silicon and boron nitride structures, have been theorized as potential materials that can form supracrystal arrangements.
2D supracrystals have many theorized properties. Although, many of the properties are variable depending on the actual structure of the supracrystal. For example, it has been theorized that the stability of 2D carbon supracrystals could either be better or worse than graphene, depending on the actual synthetic make-up. There are also many properties, such as the ability to propagate elastic waves, which are thought to be like the properties exhibited by graphene. So, in theory, there is a lot of potential for these materials, but it does depend on how efficient the synthetic process will be in creating stable structures.
Applications of 2D Supracrystals
One area where 2D supracrystals could be used is in planar nanoacoustoelectronics. 2D carbon supracrystals show the greatest potential because of their close (potential) affinity to graphene. The main property of 2D supracrystals is the ability to propagate acoustic waves efficiently. The estimations of the force constants, elastic moduli and propagation velocities of these supracrystals are very close to the values shown by graphene. In short, 2D carbon supracrystals are (theoretically) acoustically isotropic two-dimensional mediums that could be used in nanoacoustoelectronic devices.
There are many supracrystalline nanoribbons that show potential across nanoelectronic applications. To date, nanoribbons composed of carbon, silicon, sulphur and boron-nitride materials have had their properties evaluated using computational studies. Researchers have found that the boundary conditions, chemical composition and chirality permit can easily be changed in various supracrystal nanoribbons to tune their electronic properties. Overall, the energy stability and band-gap properties of these supracrystals could potentially show great promise for use in nanoelectronic devices.
Overall, 2D supracrystals have many potential application areas where 2D materials are being used. Like the 2D materials being synthesized today, 2D supracrystals have the potential to exhibit excellent electronic properties and it is most likely that these materials would be used for some form of electronics-based application.
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