Enhancement of red fluorescence and afterglow in CaTiO3: Pr3+ by addition of Lu2O3

CaTiO3: Pr3+ with addition Lu2O3 are synthesized by conventional solid-state reaction methods. It is found that the addition of Lu leads to the enhancement of red fluorescence and phosphorescence at 615 nm originating from 1D2→3H4 transition of Pr3+, following the increase of the lifetime for the 1D2 state. As a result, it is indicated that the non-radiative centers for the 1D2 state are suppressed by the addition of Lu ions. The persistent time of the afterglow is observed to increase from less than 15 min to over 2 h after the addition of 5 mol% Lu2O3. A tentative mechanism of the Lu-addition effect on the optical properties is discussed.