Impact of the structural interplay between methyl amine cation and inorganic lead-halide cage of organic perovskites on the optoelectronic properties

Energy harvesting systems using organic–inorganic metal perovskite materials are the subject of active research and development. The synthesis protocols as well as the composition, structure, and stability of these materials are still up for dispute. There are relatively few studies available correlating the relation between the optical band gap and the composition of bulk perovskite materials. Given this, the primary goal of this work is to investigate the influence of structural interplay between methyl amine cation and an inorganic lead-halide cage of organic perovskites by varying the halide functionality of lead halide. Three different products have been synthesised, namely: Methyl ammonium lead iodide-chloride (CH 3 NH 3 PbICl 2 ), methyl ammonium lead iodide-bromide (CH 3 NH 3 PbIBr 2 ) and methyl ammonium lead iodide (CH 3 NH 3 PbI 3 ). This work is a first-hand report that sheds light on the importance of the interplay between the electrostatic forces generated by the methyl ammonium group and the metal halide framework of organic perovskite on its optoelectronic properties.