Optical Spectroscopy of Ce³⁺-Activated X₂-Y₂SiO₅

Abstract

Emission and excitation spectra of X₂-Y₂SiO₅ doped with Ce³⁺ ions have been investigated at room temperature, in which Ce³⁺ ions were added by using different starting materials of CeO₂ (IV) or Ce(NO₃)₃⋅6H₂O (III). The emission spectra were analyzed on the base of a Gaussian function to investigate the detailed optical characteristics of Ce³⁺. Y₂SiO₅ doped with CeO₂ exhibited a broad spectrum with a tail in the range from 500 to 600nm. On the other hand, Y₂SiO₅ doped with Ce(NO₃)₃ gave a relatively sharp spectrum shorter than 500nm. With using fitting parameters based on Gaussian function, Y₂SiO₅ doped with CeO₂ was found to show an additional Gaussian band around 430nm in contrast to the Ce(NO₃)₃ doped one. Furthermore, the fluorescence spectra under the excitation at 330nm indicated that a broad spectrum with a peak at 430nm is only observed in Y₂SiO₅ doped with CeO₂. Such an emission spectrum is similar to the new Gaussian band at 430nm estimated from the parameter fitting. This implies that the new band actually exists, contributing to the tail of the emission spectra. These results give a new information on the occupation site of Ce³⁺ in the X₂-Y₂SiO₅ matrix.