Invited talk

Stability problems of zigzag edges in graphene nanostructures
Dimas G. de Oteyza^1,2

1 Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA; 33940 El Entrego, Spain
2 Donostia International Physics Center; 20018 San Sebastián, Spain

Carbon nanostructures with zigzag edges exhibit unique properties with exciting potential applications. Such nanostructures are generally synthesized under vacuum because their zigzag edges are unstable under ambient conditions [1]: a barrier that must be surmounted to achieve their scalable exploitation. Here, we prove the viability of chemical protection/deprotection strategies for this aim, demonstrated on labile chiral graphene nanoribbons (chGNRs) [2]. Upon hydrogenation, the chGNRs survive an exposure to air, after which they are easily converted back to their original structure via annealing (Fig. 1). We also approach the problem from another angle by synthesizing a chemically stable oxidized form of the chGNRs that can be converted to the pristine hydrocarbon form via hydrogenation and annealing. These findings may represent an important step toward the integration of zigzag-edged nanostructures in devices. Lastly, we also study the magnetism associated to remaining defects, as well as the dependence of the magnetic interactions on structural details [3].

Figure 1: STM image of a pristine (3,1)-chGNRs sample on Au(111) (a) with an associated bond-resolving image (b); after exposure to atomic hydrogen (c); and the same sample after air exposure and annealing (d), along with another bond resolving image (e).

[1] A. Berdonces-Layunta, et al., Chemical Stability of (3,1)-Chiral Graphene Nanoribbons, ACS Nano 2021, 15, 5610−5617
[2] J. Lawrence, et al., Circumventing the stability problems of graphene nanoribbon zigzag edges, Nat. Chem., 2022, 14, 1451–1458
[3] T. Wang, et al., Magnetic interactions between radical pairs in chiral graphene nanoribbons, Nano Letters 2022, 22, 164−171