2D materials are differentiated from graphene in that they are made from carbon compounds. These are generally derived from covalent organic frameworks, or metal-organic frameworks . This category will include tremendous diversity by virtue of the universe of incorporated polymers. Promising applications include nanoporous filters and membranes, as well as biosensors and optoelectronic devices.
The next group are transition metal dichalcogenides . Examples such as molybdenum disulfide and tungsten disulfide have been shown to be useful in producing fast transistors, and have been incorporated into complex integrated circuits. However, producing these is laborious and slow. Recently, a three-atom thick version has been produced more efficiently using chemical vapor deposition.
Finally, there is the group that Jacoby calls Nitrides. These are distinct from the nitrides that are included in the MXenes because instead of being made from transition metals, they are made from calcium, gallium, or boron. While calcium nitride’s high conductivity is being explored for battery applications, boron nitride shows promise as an insulator for transparent, high-speed, flexible electronics.
So, the search continues. While there is no clear frontrunner, a number of promising candidates are being studied. The biggest opportunity is likely to lie not in surpassing graphene, but to complement it in applications such as semi-conductors or insulators, as a number of these appear to be innately better suited due to their band gaps . All, or mostly all of these candidates, are made from abundant materials, so cost won’t necessarily be a concern.