Dual-mode multicolor luminescence anti-counterfeiting based on Mn-doped color-tunable MgGa2O4:Zn2+/Ge4+ phosphors

In this paper, a series of MgGa 2 -x (Zn/Ge) x O 4 :0.001Mn ( x ​= ​0, 0.05, 0.15, 0.3, 0.5, 1 and 1.2) phosphors were successfully synthesized using high temperature solid-state reaction. Under excitation at 377 ​nm, the sample has two emission peaks at 501 ​nm and 673 ​nm, respectively. In this material, Mn 2+ and Mn 4+ ions replace tetrahedral site (Mg site) and octahedral site (Ga site), respectively. The green emission at 501 ​nm belongs to the 4 T 1 (G)→ 6 A 1 (S) transition of Mn 2+ , and the red emission of 673 ​nm belongs to the 2 E → 4 A 2 transition of Mn 4+ . Design of anti-counterfeiting application pattern. (a) Pattern under daylight (b) Pattern under 365 ​nm UV light (c) Pattern after the removal of 365 ​nm UV light (d) Pattern under 254 ​nm UV light (e) Pattern after the removal of 254 ​nm UV light. • The emission color of MgGa 2 -x (Zn/Ge) x O 4 :0.001Mn were discussed. • The phosphors can emit several colors under different UV lamp by adjusting Zn 2+ /Ge 4+ doping amount. • Potential application as anti-counterfeiting materials was estimated.