Long-Lasting Phosphorescence Properties of Pyrochlore La₂Ti₂O₇:Pr³⁺ Phosphor

The La₂Ti₂O₇:Pr³⁺, 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 min, the Pr³⁺-doped La₂Ti₂O₇ phosphor emits intense red emitting afterglow from the ¹D_2→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 Pr³⁺-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.