Study of structural, optical and magnetic properties of 3D and quasi-2D iron-based lead-free perovskites

In recent years, three-dimensional hybrid perovskites (CH3NH3PbX3) with X = Cl, Br and I, due to their simple production methods and encouraging energy conversion efficiency in perovskite-based solar cells, have raised great attention. One of the main limitations in the development and application of these structures is the toxicity of lead. Investigation of the magnetic and optical properties including linear and nonlinear properties of lead-free organic–inorganic perovskites seems to be necessary. The main focus of this work is the iron substitutions at the lead site. Three-dimensional CH3NH3FeCl3 organic–inorganic perovskite and two-dimensional hybrids, (CH3(CH2)3NH3)2FeCl4 and (C6H5(CH2)2NH3)2FeCl4, were prepared. Firstly, we describe the synthesis method, crystal structure and magnetic behavior of the iron-based lead-free perovskites. Optical properties including linear and nonlinear behavior of the iron halide perovskites are also investigated. The results indicate the presence of iron oxide phase between the layers of (PEA)2FeCl4 perovskite structure and a superparamagnetic behavior with weak magnetization. Through the Z-scan approach, we observed high nonlinear optical response and high nonlinear refraction. The organic cation effect on the nonlinear absorption and nonlinear refraction is studied experimentally. The remarkable third-order nonlinear thermo-optical properties of quasi-2D/3D iron-based lead-free perovskites suggest the potential of these materials for photonics applications.