Study on visible emission of Cu-ion-doped perovskite hafnate in view of excitation energy dependence

Abstract

We studied on the visible emission of Cu-ion-doped perovskite hafnate SrHfO3 (SHO:Cu) with the photo-excitation energy dependence. The polycrystalline SHO:Cu samples were newly synthesized in the solid state reaction method. From the X-ray diffraction measurement it was found that the crystalline structure of SHO:Cu is nearly identical to that of undoped SrHfO3. Interestingly, the photoluminescence excitation (PLE) spectra change significantly with the emission energy, which is linked to the strong dependence of the visible emission on the photo-excitation energy. This unusual emission behavior is likely to be associated with the mixed valence states of the doped Cu ions, which were revealed by X-ray photoelectron spectroscopy. We compared our finding of tunable visible emission in the SHO:Cu compounds with the cases of similar materials, SrTiO3 and SrZrO3 with Cu-ion-doping.