Variable Photoluminescence Intensity Ratio with the Excitation Wavelength in Eu-Doped Perovskite-Type Alkaline Earth Zirconates─Possibility of a Unique Visualization of Ultraviolet Light.

Photoluminescence (PL) spectra arising from 4f-4f dipole transitions of Eu doped at both the and sites of perovskite-type alkaline earth zirconates obtained at various excitation wavelengths were evaluated. Changes in the excitation wavelength caused obvious differences in the PL intensity ratio of the induced electric dipole (ED) D → F transition to the magnetic dipole (MD) D → F transition for Eu-doped SrZrO and CaZrO, in which only the B site had a center of symmetry. Two charge transfer (CT) bands associated with the excitation of Eu were observed in the spectra of these oxide samples, which arose from the difference in the electronic structure of the Eu-O coordination at the A and B sites.