Full length articleThe color tunability and mechanism of upconversion emissions in Yb3+ and Er3+ co-doped Y2Ce2O7 phosphors

Y2Ce2O7 powders doped with different Yb3+ and Er3+ concentrations were synthesized via the sol-gel method. The structure and upconversion properties were investigated. The results indicated that a single phase was obtained and that the structure was cubic. The green and red upconversion emissions were detected with excitation at 980 nm, and the emission intensities could be tuned by the Yb3+ and Er3+ concentrations. The mechanism of the upconversion process was evaluated on the basis of the emission intensities and lifetimes of the 4S3/2, 4F9/2 and 4I13/2 levels. The results demonstrated that cross-relaxation was responsible for the dependence of green and red upconversion emissions on the dopant concentration.