Investigation of optical and dielectric properties of CsPbI3 inorganic lead iodide perovskite thin film

This experimental work reports refractive index, extinction coefficients, and dielectric functions at different incident angles in visible range for the first time. The refractive index of CsPbI3 thin film is 2.46 at 435 nm with this result implies that Cs based lead halide solar cells may be, ideal antireflection coating for many tandem solar cells. Thus lower refractive index of CsPbI3 inorganic perovskite material is beneficial for perovskite device fabrications because of the minimum light looses to reflection at the front of the active layer. Furthermore microstructure of the cubic phase Pm-3 m was investigated by X-ray diffraction. CsPbI3 perovskite thin film showed the sharp absorption edge and PL emission near infrared region with direct band gap of 1.67 eV with high color purity of red emission. In addition, the higher dielectric function value of CsPbI3, will helps to many optoelectronic devices. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.