Design, Synthesis, and Characterization of a Novel Blue-Green Long Afterglow BaYAl 3 O 7 :Eu 2 + , Nd 3 + Phosphor and Its Anti-Counterfeiting Application.

Herein, a series of novel long afterglow nanophosphors BaYAl 3 O 7 :Eu 2 + , Nd 3 + was synthesized by the combustion method. The investigation encompassed the characterization of X-ray diffraction, morphology, chemical valence, elemental composition, and photoluminescence behavior of BaYAl 3 O 7 :Eu 2 + and BaYAl 3 O 7 :Eu 2 + , Nd 3 + nanoparticles. Under 365 nm excitation, BaYAl 3 O 7 :Eu 2 + and BaYAl 3 O 7 :Eu 2 + , Nd 3 + show emission bands centered at 497 nm and 492 nm, which are attributed to the 4f 6 5d→4f 7 transition of Eu 2 + ions. The optimal samples of BaYAl 3 O 7 :0.03Eu 2 + and BaYAl 3 O 7 :0.03Eu 2 + , 0.02Nd 3 + have average fluorescence lifetimes of 850 ns and 1149 ns, respectively. The co-doping of Nd 3 + ions as the trap centers produced long afterglow luminescence properties, and the afterglow time could reach up to 8 min. Furthermore, the fluorescent powder can be mixed with polyacrylic acid to prepare anti-counterfeiting inks; a clover pattern and snowflake pattern have been successfully printed using screen printing technology, proving its potential application in the field of anti-counterfeiting.