Achieving Multicolor Anti‐Counterfeiting via Simultaneous X‐Ray and UV/Blue Excitation in Ca2YMgScSi3O12: Mn2+

Abstract Optical materials have attracted much attention in anti‐counterfeiting applications due to their visualization and multi‐emission modes. However, the unit occupancy predestines the material to only monochromatic emission, inhibiting the application of optical materials in advanced information encryption. Here, a green to yellow to deep‐red phosphor is reported in a Mn 2+ ‐activated garnet compound Ca 2 YMgScSi 3 O 12 : Mn 2+ (CYMSS: Mn 2+ ), originating from the abundant lattice sites occupying within the crystal structure by Mn 2+ ions. Three different photoluminescence (PL) emission bands peaked at 517, 576, and 720 nm from 4 T 1 (G) → 6 A 1 (S) are observed, which are attributed to the substitution of [Sc/MgO 6 ] octahedron and [Ca/YO 8 ] dodecahedron sites by Mn 2+ ions, respectively. Hence, tunable emissions from green to deep‐red are realized in single Mn 2+ doping by switching the excitation source of ultraviolet (UV)/blue and X‐ray, which can be further regulated by varying the Mn 2+ concentration. Multi‐position occupying, color‐tunable light‐emitting materials offer the possibility of more advanced optical information encryption.