纳米医学与纳米技术杂志

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Investigation of Optical and Dielectric Constants of Organic-Inorganic CH3NH3PbI3 Perovskite Thin Films

Ailing Yang, Bai M, Bao X, Wang J and Zhang W

CH₃NH₃PbI₃ thin films with thicknesses in the region of 230-365 nm were prepared. The films were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), ultraviolet-visible (UV-Vis) absorption and transmittance spectra. Based on the Kramers-Kronig relation and the transmittance spectra, the optical constants of the CH3NH3PbI3 thin films were investigated. Our results show that the absorption coefficient, extinction coefficient, refractive indices, real and imaginary components of the dielectric constant of the CH3NH3PbI3films are basically independent on the thicknesses of the films, which indicate our results are reliable. At 500 nm, above parameters of the films are ~1.38 × 105 cm-1, 0.55, 2.70, 7.01, and 3.13, respectively. The band gap is 1.595 eV. The refractive index of CH3NH3PbI3thin films is 2.84 at 633 nm, which imply that CH₃NH₃PbI₃-based solar cells are ideal antireflection coatings for silicon solar cells (SCs) and are applicable to be top solar cell in monolithic silicon-based tandem solar cells for beyond the efficiency limit of Si SCs. Our results are meaningful for designing optoelectronic devices related to the perovskite thin-films.