Spectral Studies of Lead‐Free Organic‐Inorganic Hybrid Solid‐State Perovskites CH ₃ NH ₃ Bi _2/3 I ₃ and CH ₃ NH ₃ Pb _1/2 Bi _1/3 I ₃ : Potential Photo Absorbers

Abstract

Abstract The spectral analysis of bismuth based halide perovskite materials has been carried out using FTIR, UV‐Vis, photoluminescence and fluorescence time resolved spectroscopy. Methylammonium bismuth iodide (CH 3 NH 3 Bi 2/3 I 3 ) has shown promising results to become a potential candidate for the replacement of lead based organic‐inorganic hybrid halide perovskite solar cells, having superior moisture stability and environmentally benign nature. The lead and bismuth both have been used to synthesize methylammonium lead bismuth iodide (CH 3 NH 3 Pb 1/2 Bi 1/3 I 3 ) to develop an intermediate photo absorber to counter the moisture degradation properties as well as the low absorbance of bismuth based perovskites. Spectral studies have revealed information about electron transitions, phase separation and exciton recombination time.