Multi-color afterglow phosphor via energy transfer in Sr ₃ In ₂ Ge ₃ O ₁₂ :Bi ³⁺ , Sm ³⁺ for information encryption and anti-counterfeiting

Traditional persistent luminescent materials are facing significant challenges in achieving multi-color anti-counterfeiting and visualization. Here, this study proposes a novel, to the best of our knowledge, multi-mode anti-counterfeiting strategy based on Sr 3 In 2 Ge 3 O 12 :x%Bi 3+ -y%Sm 3+ . By exploiting the energy transfer effect from Bi 3+ to Sm 3+ and adjusting the dopant concentration, continuous modulation of photoluminescence and afterglow emission from blue, yellow to orange is realized via regulating dopant concentrations. Based on systematic spectroscopic analysis, the corresponding energy transfer and afterglow mechanisms have been elucidated; this mechanism requires no complex multi-component doping systems and offers the advantages of ease of control and high stability. This work provides an effective strategy for developing multi-mode visual luminescent materials and broadens the application scope of afterglow phosphors in high-security information storage.