Experimental and Theoretical Characterization of the Optical Properties of CeO2, SrCeO3, and Sr2CeO4 Containing Ce4+ (f0) Ions

In an effort to find new UV absorbers, the optical properties of CeO2, SrCeO3, and Sr2CeO4 were examined by UV-visible diffuse reflectance measurements and electron energy-loss spectroscopy (EELS), and their electronic structures were investigated on the basis of first-principles density functional theory (DFT) calculations. The extinction coefficient k and the refractive index n determined from the loss function Im(-1\) by EELS were compared with the corresponding quantities calculated from DFT calculations. The UV absorption thresholds of these materials were determined by the electron excitation from the O 2p anionic band to the empty Ce 4f orbitals. The calculated and measured refractive indices were in satisfactory agreement. The applicability of CeO2, SrCeO3, and Sr2CeO4 as potential UV absorbers was assessed