Effect of Electron Transporting Layer on Bismuth-Based Lead-Free Perovskite (CH3NH3)3 Bi2I9 for Photovoltaic Applications

Methylaminonium iodo bismuthate ((CH3NH3)(3)Bi-2-I-9) (MBI) perovskite is a promising alternative to rapidly progressing hybrid organic inorganic lead perovskites because of its better stability and low toxicity compared to lead-based perovskites. Solution-processed perovskite fabricated by single-step spin-coating and subsequent heating produced polycrystalline films of hybrid perovskite (CH3NH3)(3)Bi-2-I-9, whose morphology was influenced drastically by the nature of substrate's. The optical measurements showed a strong absorption band around 500 nm. The devices made on anatase TiO2 mesoporous layer showed good performance with current density over 0.8 mA cm(-2) while the devices on brookite TiO2 layer and planar (free of porous layer) was inefficient. However, all the MBI devices were stable to ambient conditions for more than 10 weeks.