Electronic and aromatic properties of graphene and nanographenes of various kinds: insights and results 

Aristides D. Zdetsis1,2*, Eleftherios N. Economou2

1Molecular Engineering Laboratory, Department of Physics University of Patras, Patra, 26500 GR, Greece

2Institute of Electronic Structure and Laser, Foundation for Research and Technology, Vassilika Vouton, P.O. Box 1385, Heraklion 71110 GR, Greece

Adv. Mater. Lett., 2017, 8 (3), pp 256-261

DOI: 10.5185/amlett.2017.7104

Publication Date (Web): Jan 28, 2017

E-mail: zdetsis@upatras.gr

Abstract


Using suitable Density Functional Theory (DFT) methods and models of various sizes and symmetries, we have obtained the aromaticity pattern of infinite graphene, which is an intrinsically collective effect, by a process of “spatial” evolution. Using a similar process backwards we obtain the distinct aromaticity pattern(s) of finite nanographenes, graphene dots, antidots, and graphene nanoribbons. We have shown that the periodicities in the aromaticity patterns and the band gaps of graphene nanoribbons and carbon nanotubes, are rooted in the fundamental aromaticity pattern of graphene and its size evolution, which is uniquely determined by the number of edge zigzag rings. For graphene antidots the nature of the aromaticity and related properties are largely depended on the degree of antidot passivation. For atomically precise armchair nanoribbons (AGNRs), the aromaticity and the resulting band gaps, besides the number of zigzag rings which determines their widths, are also depended on the finite length of the ribbons, which is usually overlooked in the literature. Thus, we have fully rationalized the aromatic and electronic properties of graphene and various nanographene(s) and we have bridged some of the observed discrepancies for the band gaps in atomically precise AGNRs by judicially introducing the “effective” band gaps as well.

Keywords

Aromaticity, nanographenes, graphene antidots, graphene nanoribbons.

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