Influence of adding 5-ammonium valeric acid bomide on the linear and nonlinear optical properties of formamidinium lead bromide perovskite films

Formamidinium lead bromide films doped with 5-Ammonium Valerie Acid Bromide, (FA)(1-x)(AVABr)(x)PbBr3 (0 <= x <= 0.25), were prepared using the spin coating method. X-ray diffraction analysis revealed that the percentage of alpha-FAPbBr(3) to delta-FAPbBr(3) phases is dependent on the amount of AVABr. The effect of increasing the concentration of AVABr in the formed film on the absorption band edge, absorbance, reflection, transmittance, absorption coefficient, extinction coefficient, refractive index, (real and imaginary) parts of the dielectric constant, (surface and volume) energy loss functions, (optical and electric) conductivities, and non-linear optical parameters (NLO) behaviors was studied in detail. All films displayed a limited reflection in the visible range (under 18%). The transmittance of the films doped with 5 and 10% AVABr became 83 and 85% as compared with the FAPbBr(3) film (72%) at 600 nm. The optical band gap changed slightly between 2.26 and 2.29 eV depending on the amount of AVABr in the film. The high values of sigma(opt) and sigma(ele) for the films doped with 5 and 10% AVABr are good indicators for the possible application of both films in optoelectronic applications. Films containing 5 and 10% AVABr have the highest NLO values. All films exhibited a single asymmetry peak located in the green emission range (542-549 nm).