Optoelectronic and Photovoltaic Properties of (NH4)3Bi2I9: A Perovskite-like Energy Material for Pb-free Perovskite Solar Cells

Recent few years have witnessed a tremendous surge in the design and fabrication of lead (Pb)-free perovskite or perovskite-like materials for the development of perovskite solar cells (PSCs). Bismuth halide perovskite materials such as (CH3NH3)(3)Bi2I9, Cs3Bi2I9 and FA(3)Bi(2)I(9) have been utilized as highly efficient perovskite light absorbers in terms of aerobic stability. Herein, we have investigated the optoelectronic properties of the (NH4)(3)Bi2I9 perovskite and employed as light absorber in the construction of Pb free PSCs. Solvent engineering approach was utilized to improve the photovoltaic performance of the (NH4)(3)Bi2I9 perovskite based PSCs. The probable HOMO and LUMO energy level values of the (NH4)(3)Bi2I9 perovskite were also investigated and the band gap of the (NH4)(3)Bi2I9 perovskite was found to be of 2.1 eV. The developed PSCs device exhibited the power conversion efficiency (PCE) of similar to 0.6%.