Increased 1D2 Red Emission of Pr3+ in NaGdTiO4:Pr3+ Due to Temperature-Assisted Host Sensitization and Its Color Variation

Temperature-dependent luminescent property of Pr 3+ -doped NaGdTiO 4 is investigated systematically. Because of the intensive quenching of 3 P 0 emission, a red emission of 1 D 2 – 3 H 4 transition is observed in NaGdTiO 4:Pr 3+ at room temperature (RT). At 77 K, a broad band emission of host at about 475 nm (blue) is observed. Interestingly, the intensity of the red emission is increased with increasing temperature from 77 to 350 K and keeps nearly stable to 400 K under the host excitation, whereas a decrease of the blue host emission is presented. The results show that the increased red emission of 1 D 2 is associated with temperature-assisted energy transfer from host to Pr 3+ . Because the relative intensity of the 1 D 2 and host emission is sensitive to temperature, a large variation of color is also observed from 77 K to RT.