Effect of reaction time and different solvents ratios on the formed phases and optical properties of formamidinium lead bromide

Abstract

Formamidinium lead bromide (FAPbBr3) thin films were prepared using two different solvents (N, N-Dimethylformamide, DMF and Methyl sulfoxide, MSO) with different ratios (1 DMF: 4 MSO and 4 DMF: 1 MSO) and different reaction times (4 h and 24 h). The effect of different solvents ratios and reaction time on the crystallinity and different phases percentage was examined using x-ray diffraction technique. Also, the influence on the transmittance, reflectance, absorbance coefficient, refractive index, extinction coefficient, real and imaginary parts of the dielectric constant and optical conductivity for FAPbBr3 thin films was explored using UV–vis spectrophotometer. All films showed interference, which verifies the high crystallinity of the films as confirmed from XRD data. The refractive index exhibited multi-oscillating peaks. The optical band gap energy for the FAPbBr3 perovskite thin films changed slightly either with varying the ratio between the solvents used in the preparation or the reaction time. FAPbBr3 thin films prepared with 1 DMF: 4 MSO are excellent nonlinear optical materials. FAPbBr3 perovskite thin films prepared with 1 DMF: 4 MSO exhibited the strong photoluminescence intensity and narrow full width at half maximum intensity.