Enhancement the electronic and optical properties of the graphene nanoflakes in the present S impurities

Electronic and optical properties of the graphene nanoflakes (GNFs) are investigated with and without various concentrations of S impurities in different locations via a time-dependent density-functional theory (TDDFT) calculation. Results showed very fascinating results. Results showed up that the pristine GNFs have a semi-conductor behavior. S-doped GNFs also have a semiconductor behavior with reducing electronic band gap value. The band gap of the GNFs is reduced by altering the location of the S impurity. Correspondingly, it is decreased by increasing the concentration of the S impurity. Also, when the concentration of S goes up, the total and formation energies are increased with negative sign, which means the structures became more stable and exothermic process. Our findings show lambda maxalso depends on the site and concentrations of S impurity, which is taken value from 474.54 to 12514.22 nm for pristine and 3S-PNG (a) cases, respectively. Correspondingly, we observed that the sturdy absorption peaks (pristine, 1S-PNG (a), 4S-PNG (b)) cases are in the visible light and near-infrared region. In brief, the optoelectronics properties of the GNFs are dependent on the position and concentrations of S impurities.