Influence of Ni doping in a lead-halide and a lead-free halide perovskites for optoelectronic applications

Metal halide perovskites have become more popular for applications in solar cells and optoelectronic devices. In this study, the structural, electronic, mechanical, and optical properties of lead and lead-free metal halide cubic perovskites CsPbBr3 and CsGeBr3 and their Ni-doped structures have been studied using the first-principle density functional theory. Ni-doped CsGeBr3 shows enhanced absorbance both in the visible and the ultraviolet region. The absorption edge of Ni-doped CsBBr3 (B = Pb, Ge) shifts toward the lower energy region compared to their undoped structures. Undoped and Ni-doped lead and lead-free halides are found to have a direct bandgap, mechanical stability, and ductility. A combined analysis of the electronic, mechanical, and optical properties of these compounds suggests that lead-free perovskite CsGe0.875Ni0.125Br3 is a more suitable candidate for solar cells and optoelectronic applications.