Optical constants of CH₃NH₃PbBr₃ perovskite thin films measured by spectroscopic ellipsometry.

The lack of optical constants information for hybrid perovskite of CH₃NH₃PbBr₃ in thin films form can delay the progress of efficient LED or laser demonstration. Here, we report on the optical constants (complex refractive index and dielectric function) of CH₃NH₃PbBr₃ perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained from photoluminescence and spectrophotometry spectra, and calculated from the SE analysis. The precise measurement of optical constants will be useful in designing optical devices using CH₃NH₃PbBr₃ thin films.