posted on 2023-11-16, 17:47authored byZishuo Yi, Peng Liu, Xia Liu, Yan Xu
Persistent luminescence (PersL) materials with impressive
superiorities
in optical performance have shown tremendous potential for information
encryption application. Herein, a Bi3+-doped LiGa5O8 PersL material is facilely synthesized by a simple
solid-state reaction. Site selective and preferential occupation of
Bi3+ ions at distinct Ga3+ and Li+ polyhedra sites in LiGa5O8 endows it with
a bimodal emission at 511 and 718 nm upon UV excitation at 254 nm.
After removing the light source, an intense red afterglow was observed
due to the generation of more and deeper traps classified as the oxygen
vacancy defect (VO••) and the impurity defect (BiLi••). It is rarely
reported in inorganic phosphors to achieve the Bi3+ single
doping-activated red PersL. The LiGa5O8:x% Bi3+ (with x = 0.5–5.0)
samples also exhibit tunable PL and time-dependent PersL properties.
Combined with the Morse Code, a multiple information encryption model
based on the abnormal optical properties of LiGa5O8:x% Bi3+ (x =
0, 0.5, and 5.0) samples was designed for high-level dynamic anticounterfeiting.
These achievements further validate the use of the Bi3+ single doping strategy to explore excellent PersL materials and
expand their multifunctional optical applications.