NaNbO3:Pr3+: a new red phosphor showing persistent luminescence

The Pr(3+)-doped NaNbO(3) perovskite is introduced as a new red phosphor excitable in the near UV region at around 350 nm. A bright single red emission is observed at room temperature and ascribed to transitions between the (1)D(2) excited state and the ground state (3)H(4) of Pr(3+) ions. This peculiar behavior is related to the presence of a low-lying intervalence charge transfer state that contributes to quench the emission from the otherwise emitting (3)P(0) level. Red afterglow is also evidenced in NaNbO(3):Pr(3+). A preliminary model is discussed to clarify the afterglow mechanism.