Effect of impurity substitution on band structure of hybrid perovskites for photovoltaic applications

The hybrid halide perovskites due to their specific properties have gained strong interest as photon absorbers in solar cells and opened new ways to develop high efficiency and low cost photovoltaic devices. In this study, we have reported the structural and electronic properties of the CH3NH3PbI3 perovskite in the framework of density functional theory. The band structure and density of states have been calculated. According to the results, this perovskite has a direct band gap value of 1.6 eV and is semiconductor. All results showed a good agreement with other experimental and theoretical studies. In the second part, the effect of fluorine doping on the structural and electronic properties of new structure CH2FNH3PbI3 was predicted. Our results reveal that fluorine doping narrows the electronic band gap and affects affects the composition of the valence band maximum and so the effective mass of the holes in the valance band