Low-temperature red long-persistent luminescence of Pr3+ doped NaNbO3 with a perovskite structure

Abstract Long persistent luminescence (LPL) phosphors can keep emitting light after the removal of excitation sources under thermal disturbances at room temperature, which provides a wide application from emergency signs to in vivo biological imaging. Unfortunately, these phosphors will exhibit poor LPL performance once the thermal activation energy is not sufficient to release the captured carriers from the traps at low-temperature. Herein, a red phosphor of Pr 3+ doped NaNbO 3 with a perovskite structure is designed, which realizes a low-temperature LPL. The red emission (λ em = 612 nm) is ascribed to the 1 D 2 → 3 H 4 transition of Pr 3+ ions, and LPL can be visually recognized over 16 h after the removal of the excitation source at 200 K. Low-temperature thermoluminescence curves, temperature-dependent photoluminescence spectra indicate that abundant traps (≤ 0.6 eV) exist in NaNbO 3 : Pr 3+ , which is critical for ensuring the low-temperature LPL. The investigation on low-temperature LPL properties of NaNbO 3 : Pr 3+ helps us to reveal the importance of defects structure, and provides new opportunities in exploring luminescence materials applied in an extreme conditions.