First-principles study of shear deformation on the photovoltaic properties of F-doped SnSe₂

Abstract Based on the fundamentals of density functional theory (DFT), this work examines how shear deformation affects the optoelectronic characteristics of the F-doped SnSe 2 system. First, the electronic structure of the SnSe 2 system (X-SnSe 2 ) doped with halogen X (X = F, Cl, Br, I) is computed. This calculation shows that the SnSe 2 system changes from semiconductors to metal when doped with halogens. Following this, the formation and binding energies of the X-SnSe 2 system are analyzed. The formation energy of the X-SnSe 2 system ranges from −0.598 to 0.143, with lower formation energies indicating greater stability of the system. Therefore, the F-SnSe 2 system, with a formation energy of −0.598, is the lowest among the four doped systems, and no imaginary frequencies were found in the phonon spectrum of the F-SnSe 2 system. Hence, this indicates that the F-SnSe 2 system is stable. Its electrical properties show that shear deformation can transform the F-SnSe 2 system from metal to semiconductor. Furthermore, the system’s optical properties demonstrate that shear deformation results in a blue shift of the absorption, reflection, and loss peaks, enhancing the F-SnSe 2 system’s light absorption and concurrently reducing its energy dissipation.