Green and red upconversion luminescence in CeO2:Er powders produced by 785 nm laser

CeO₂:Er³⁺ powders were prepared by Pechini type sol-gel method. The structural properties of CeO₂:Er³⁺ were studied by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectra. The results show that CeO₂:Er³⁺ has low phonon cutoff energy, which indicate that CeO₂:Er³⁺ may have high luminescent efficiency. The green and red upconverted luminescence spectra of Er³⁺ were investigated under excitation into the ⁴I_9/2 level by 785 nm laser. The upconversion mechanisms were studied in detail through laser power dependence and Er³⁺ ions concentration dependence of upconverted emissions, and results show that excited state absorption and energy transfer process are the possible mechanisms for the upconversion. The upconversion properties indicate that CeO₂:Er³⁺ may be used in upconversion phosphors.