Modeling the polymorphic varieties of L4-6-12 graphene functionalized by hydroxyl group

M. E. Belenkov ; V. A. Greshnyakov ; V. M. Chernov

Vestnik Ûžno-Uralʹskogo gosudarstvennogo universiteta. Seriâ, Matematika, mehanika, fizika, Tome 14 (2022) no. 4, pp. 52-58

Résumé

Density functional theory in the generalized gradient approximation was used to model three new polymorphic varieties of graphene functionalized by the hydroxyl group, consisting only of paired topological defects 4-6-12. Layer modeling was carried out for primitive hexagonal elementary cells with the types of addition of the hydroxyl group T1, T2, T3. Each of the elementary cells contained 36 atoms. As a result of the calculations, it was established that the carbon frame of the initial layer remains stable during functionalization for the T1 and T3 types, while the functionalized layer T2 undergoes destruction. The layer density in hydroxygraphene layers L4-6-12 with attachment types T1 and T3 is 1,34 and 1,36 mg/m$^{2}$, respectively. This is less than the layer density for similar fluorographene layers by 0,08-0,16 mg/m$^{2}$. The sublimation energies of stable layers T1 and T3 were 18,16 and 17,37 eV/(COH), respectively. Densities of electronic states and band structures were calculated, in order to determine the band gaps. The value of the band gap width was determined as equal to 3.33 eV for the T1 layer and 1,93 eV for the T3 layer. This enabled the layers thus obtained to be identified as semiconductors.

Détail

Mots-clés : graphene, ab initio calculations, polymorphism
Keywords: hydroxyl group, electronic properties, crystal structure, functionalization.