Investigation of MASnI<i>_x</i>Br_3-<i>x</i> (<i>x</i>=3, 2, 1, 0) Perovskite Thin Films Produced by Ultrasonic Spray Pyrolysis Method

Methylammonium iodide (MAI) and methylammonium bromide (MABr) reactants were synthesized in powder form. Tin-based perovskites (MASnI(x)Br(3-x) (x = 3, 2, 1, 0)) were deposited as a thin film on glass substrates using the ultrasonic spray pyrolysis (USP) method. X-ray diffraction (XRD) was used to examine the crystallographic characteristics of the synthesized MAI/MABr powders and perovskite thin films. A shift occurred in the XRD peaks by changing the I/Br ratios. Morphological analysis of the MAI and MABr were carried out by scanning electron microscopy (SEM). While the average particle size was calculated a similar to 94 mu m for MAI, it was obtained as similar to 188 mu m for MABr. The Fourier transform infrared (FTIR) spectroscopy peaks observed for synthesized MAI and MABr were found to be compatible with commercial MAI and MABr FTIR peaks. Elemental analysis of MASnI(x)Br(3-x) (x = 3, 2, 1, 0) perovskite thin films was performed energy dispersive spectroscopy (EDS). Forbidden band gap (E-g) values of perovskite thin films were obtained from Tauc curves. The E-g value increased with an increasing I/Br ratio. The deposition of highly stoichiometric MASnI(x)Br(3-x) perovskites thin films was achieved by the USP method. This method has many parameters need to be optimized. This study gives optimum parameters that are difficult to determine.