Effects of Fe doping on the visible light absorption and bandgap tuning of lead-free (CsSnCl3) and lead halide (CsPbCl3) perovskites for optoelectronic applications

The halide perovskite solar cells nowadays have emerged as a potential candidate for photovoltaic technology because of their high efficiency, low-cost, and facile fabrication process. In this study, the structural, elastic, electronic, and optical properties of pure and metal (Fe) doping lead-free perovskite CsSnCl3 and lead halide perovskite CsPbCl3 have been calculated by using density functional theory. The present study shows that the metal doping exhibits high absorption and high conductivity than the pure counterpart due to reducing the bandgap. The bandgap of Fe-doped CsSnCl3 is narrowing more than Fe-doped CsPbCl3. The Fe-doped CsSnCl3 reveals a more enhanced optical nature than the Fe-doped CsPbCl3 owing to the greater shipment of absorption peaks toward the lower energy region and the narrowing bandgap. The mechanical parameters show that the pure and Fe-doped samples are mechanically stable. The failure mode indicates that the Fe-doped perovskites are highly ductile in nature as pristine samples, which makes them suitable for use in thin films. The electronic band structure of doped samples exhibited the intermediate state (donor level) in the bandgap. The creation of intermediate states helps the excited photoelectron to easily transfer from the valence to the conduction band. A combined analysis of metal doping in lead halide and lead-free halide demonstrated that Fe-doped CsSnCl3 is more promising to use in solar cells and other optoelectronic applications.