Structure and electronic properties of 3-12 fluorographene crystals

The three-dimensional structure of crystals formed from 3-12 fluorinated graphene layers packed in stacks was found using the atom-atom potential method. Calculations of the electronic properties of CF-L$_{3-12}$ crystals were conducted using the method of density functional theory in the generalized gradient approximation. As a result of the calculations, it was established that the distance between the layers in crystals corresponding to the minimum energy of interlayer bonds is 5,7578 Å, and the absolute value of the shift vector of the adjacent layers is 1,4656 Å. The electronic structure of three-dimensional crystals differs from the electronic structure of 3-12 isolated fluorographene layers. The obtained value of the band gap in bulk crystals is 3,03 eV, which is about 12 % less than in a separated CF-L$_{3-12}$ layer (3,43 eV). The calculated value of the specific sublimation energy of 3-12 fluorographene crystal is 13,83 eV / (CF), which is 0,06 eV higher than the sublimation energy of the isolated fluorographene layer.