Multi–Mode Anti–Counterfeiting Using Pr ³⁺ , Ce ³⁺ and Er ³⁺ Codoped Mg ₃ Y ₂ Ge ₃ O ₁₂ Phosphor with Spatial and Temporal Luminescence Properties

Abstract Counterfeiting has become increasingly sophisticated, creating a growing need for advanced anti–counterfeiting technologies. Luminescent materials, with their unique emission properties, show promise but often lack the multifunctionality required for high–level security. Most current materials provide only one or two anti–counterfeiting modes, limiting their effectiveness. Here, a Pr 3+ , Ce 3+ , and Er 3+ codoped Mg 3 Y 2 Ge 3 O 12 (MYG) phosphor is developed with multi–mode anti–counterfeiting capabilities, including up–conversion, down–conversion, optically stimulated luminescence, thermoluminescence, X–ray luminescence, and mechano–luminescence. This material's uniqueness lies in its ability to provide diverse spatial anti–counterfeiting modes under various excitation conditions. Additionally, after various triggering methods, the material exhibits afterglow, with its color changing over time due to the varying decay rates of different Pr 3+ spectral components. This enables a novel temporal anti–counterfeiting mode. Thus, the MYG phosphor offers multi–mode anti–counterfeiting across spatial and temporal dimensions, addressing the demand for integrated, multifunctional anti–counterfeiting systems.