Effect of annealing on the spectroscopy performance of YVO4:Ce3+ single crystals

• The experiment tests showed Ce4+ and Ce3+ ions coexisting in YVO4:Ce3+ crystal.
• Ce4+ ions can be effectively reduced to Ce3+ via annealing in reduced atmospheres.
• With a fixed annealing time in H2, the luminescent intensity significantly increased with increasing annealing temperature.

In this study, 1.0 at.% YVO4:Ce3+ single crystals were grown in the protective atmosphere by using the Czochralski method. The crystals were annealed in Ar and H2 atmospheres at different temperatures. The absorption and fluorescence spectra of the samples before and after annealing were measured. Results showed that the luminescent efficiency of the crystals was significantly enhanced after annealing in H2 than after annealing in Ar. This phenomenon can be attributed to the existence of some Ce4+ ions in the crystal lattice. These Ce4+ ions can be effectively reduced to Ce3+ via annealing in H2. With a fixed annealing time in H2, the luminescent intensity significantly increased with increasing annealing temperature. The possibility of the crystal as white light material was also discussed according to the luminescence properties.