Computational and experimental studies of optical absorption properties of perovskite-layered SrO(SrTiO3)n (n = 1, 2, … , ∞)

SrO(SrTiO3)n (n = 1, 2, …, ∞) powders were prepared by a modified sol-gel self-propagating combustion method and characterized by ultraviolet-visible (UV-vis) absorption spectroscopy and infrared spectra. UV-vis spectra indicate that the absorption edge of SrO(SrTiO3)n (n = 1, 2) shift to the violet with the decrease of n value, and the band gap values obtained from the UV-vis spectroscopy measurements are 3.41 and 3.26 eV, respectively. The infrared spectra show that the width of absorption band of TiO6 octahedron stretching vibration decreases with the increasing of n value. The optical absorption of the compounds SrO(SrTiO3)n (n = 1, 2, …, ∞) were investigated by theoretical caculation using density functional theory (DFT). The interband transitions were assigned according to the partial density of states (PDOS). The calculated results are close to the experimental results.