Preparation and Characterization of Organic Inorganic Hybrid MAPbI2Br Perovskite

In this work, perovskite compounds were prepared and studied by using chemical methods for methyl ammonium halide MABr and lead halide PbI2. The main objective of the study is to successfully prepare new types of perovskites using the one-step method by changing the weight ratios of lead halide PbI2 in a fixed weight ratio of methyl ammonium bromide MABr, where they were classified into samples P1 which represents MABr/PbI2 weight ratios (0.22:0.39)g, P4 which represents MABr/PbI2 weight ratios (0.22:0.59)g and P7 which represents MABr/PbI2 weight ratios (0.22:0.79)g and the impact of this change was studied. High crystallinity was obtained in the crystal structure of the P4 sample after increasing the weight ratio of lead halide from 0.39 g to 0.59 g.  Then the crystallization decreased and the crystal structure changed after increasing the weight ratio from 0.59 g to 0.79 g in the sample P7. The increase in PbI2 weight from 0.39 g to 0.59 g and 0.79 g affected the absorption edge and shifted widely towards long wavelengths (red shift) from 625 nm to 691 nm and 805 nm.  The energy band gap changed from 1.98 eV to 1.79 eV and to 1.53 eV. The study showed that the surface morphology of these samples, where a sample with a homogeneous film with a high density was obtained, resulted from an increase in the weight of lead halide from 0.39 g to 0.59 g and with small Nano-diameters of 34.25 nm for the P4 sample. After increasing the weight from 0.59 g to 0.79 g, a sample was obtained with a less dense membrane that contains many voids and a semi-micro large particle diameter is 97.32 nm for the sample P7. Finally, the sample P4 was selected with good crystalline and optical properties and a homogeneous surface formation with a high density that could enter into the special composition for the manufacture of optical devices with high efficiency and stability.