Heterostructure-induced enhanced persistent luminescence for low temperature applications

Abstract

We report a strategy to enhance the low-temperature persistent luminescence (LT PersL) in perovskite oxides through the formation of a heterostructure, i.e. NaNbO3-LiNbO3 with Pr3+ dopants, via the defect engineering method. Prominent LT PersL was realized when the Na/Li ratio was 0.6/0.4, with the red emission still visible over 1 h after the cessation of charging at 253 K. The PersL-enhancement mechanism is elucidated with elaborate structural characterization and density functional theory calculations. The introduction of the heterostructure increased electron–hole recombination efficiency, generated long-distance photogenerated carriers, and created a pathway for successive shifts in the band structure between NaNbO3 and LiNbO3 to form shallow broad traps with broad distribution. The promising applications of these materials in dynamic information encryption and anti-counterfeiting fields at low temperatures are demonstrated.