Electronic structure of hybrid pentaheptite carbon nanoflakes containing boron-nitrogen motifs
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ORIGINAL PAPER
Electronic structure of hybrid pentaheptite carbon nanoflakes containing boron-nitrogen motifs Cesar Gabriel Vera de la Garza 1 & Wilmer Esteban Vallejo Narváez 1 & Luis Daniel Solís Rodríguez 1 & Serguei Fomine 1 Received: 14 October 2019 / Accepted: 23 February 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The electronic structure of isomeric graphene nanoflakes (NFs) heavily doped with boron and nitrogen atoms has been explored. Dispersion-corrected B3LYP functional has been used for the geometry optimizations. A complete active space method has been used for the energy evaluations. Combined boron and nitrogen doping promotes polyradicalic antiferromagnetic ground states in the NFs and affects the nanoflake geometry. There is a charge transfer from boron to nitrogen atoms which increases with the doping level. This transfer does not involve carbon atoms. Combined doping reduces both the ionization potentials (IPs) and the electron affinities (EAs) of the NFs similar to nitrogen doping alone. Boron does not affect either IPs or EAs being neither n- nor p-type dopant for the isomeric graphene NFs. All hybrid NFs show a tendency to increase the band gaps with doping level, which is promoted by the increment of the bond length alternation with doping. Finally, the hole reorganization energies for the NFs were found to be lower than the electronic ones, positioning the hybrid NF as hole-transporting systems. Keywords Nanoflakes . Pentaheptites . Doping . Relaxation energies
Introduction For many decades, the materials chemistry has been focused either on solids (3D systems) or 1D systems (polymers); the importance of two-dimensional (2D) materials has somehow been overlooked until the preparation of 2D MoS2 by the exfoliation from bulk [1]. However, it was not until graphene was prepared [2] that the relevance of 2D materials was fully recognized, and they become one of the mainstreams in the materials chemistry. 2D materials possess very attractive properties for a variety of applications [3–5]. Graphene has a honeycomb 2D structure consisting of sp2 carbon atoms; this geometry is not unique only for carbon atoms and can be found in inorganic analogs of graphene [6]. Nevertheless, the ability of carbon atoms to form strong homonuclear C–C bonds Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00894-020-4324-9) contains supplementary material, which is available to authorized users. * Serguei Fomine [email protected] 1
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, CU, Coyoacán, 04510 México, DF, Mexico
allows for existence, at least theoretically, of multiple allotropies [7, 8] even if only sp2 hybridization is considered, which corresponds to a group with n = 2 according to Heinemann denomination [9]. The sp2 hybridization leads to the essentially plane 2D carbon allotropies. Many of them have been discovered theoretically; however, none of those allotropies have
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