Electronic structures and bonding of graphdiyne and its BN analogs: Transition from quasi-planar to planar sheets

Abstract

We demonstrate a possible structural transition from graphdiyne (GDY) to boron nitride (BN)-diyne (C90-18n(BN)9nH18; n = 0-5) sheets using the density functional theory (DFT). The aim of this study is to investigate the effects of substitution of carbon atoms by B and N atoms on structural, electronic and reactivity properties. We found that a structural transition from quasi-planar to planar occurs at n = 2. The stability decreases with increasing the number of B/N. Moreover, the pristine BNdiyne is only less stable than pristine GDY by about 0.92 eV/atom. Our calculations also show that the energy gap (Eg) of the GDY and its BN structural analog models changes in the wide range of 0.45–5.52 eV as the number of B and N atoms increases in the system. The Eg of the BNdiyne (n = 5) is found to be 5.52 eV, indicating electrically an insulating behavior, however, it is 0.45 eV for the BNdiyne (n = 4) which is higher conductivity than that of pristine GDY. Molecular dynamics simulations show that temperature induces a decrease in the Eg due to variations of the bond energy and deformation in the structures under heat treatment. The ELF analysis also confirms that the B–N bonds in new GDY-like BN sheets potentially exhibit covalent characteristics. Our results herein show that new BNdiyne sheets can be used in promising applications from chemical nanosensors to solar cell applications. © 2020 Elsevier B.V.