Long-Lasting Phosphorescence Properties of Pyrochlore La2Ti2O7：Pr^3＋ Phosphor

The La2Ti2O7：Pr^3＋, which emits red color luminescence upon UV light excitation, is prepared by the conventional high-temperature solid-state method and its luminescent properties are systematically investigated. X-ray diffraction, photoluminescence, afterglow emission spectra and long-lasting phosphorescence （LLP） decay curves are used to characterize this phosphor. After irradiation by a 290-nm UV light for 3 rain, the Pr^3＋-doped La2Ti2O7 phosphor emits intense red emitting afterglow from the ^1D2 →^ 3H4 transitions, and its afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source. The afterglow decay curve of the Pr^3＋-doped La2Ti2O7 phosphor contains a fast decay component and another slow decay one. The possible mechanism of this red light emitting LLP phosphor is also discussed based on the experimental results.