▎ 摘　　要

First-principles density functional theory (DFT) calculations were performed to study the electronic structure of pristine bilayer graphene nanoflakes (BGNFs) and nitrogen (N), boron(B) and boron nitride (BN) doped BGNFs. The pristine BGNTs displayed wide-band gap semiconducting properties. The effect of the bilayer spacing was studied by varying the distance between the flakes from 4 A to 8 A which showed an increase in the band gap value from 3.33 eV to 3.46 eV, respectively. By adding N, B and BN atoms at the center between the bilayer, the band gap of the BGNFs was narrowed to 0.09 eV - 1.9 eV. The aforementioned findings clearly reveal that the spacing between the bilayer along with the doping types changes significantly the induced band gap. The total energy and dipole moment were also shown to be affected by the spacing between the layers. In particular, total energy was decreased as the spacing between layers increased while the dipole moment was increased by increasing the distance between BGNFs layers comparing with pristine cases. The capability of manipulating the electronic properties of the BGNFs via changing bilayer spacing and doping atoms open up the opportunity of tuning the band gap as needed for many applications including a solar cell, photo, and gas sensor as well as energy storage nanodevices.