Achieving multi-excitation in lanthanide-based Cs2NaTbCl6:Ce/Yb double perovskite single crystals for anti-counterfeiting

Lanthanide-doped inorganic perovskite luminescent materials have always been regarded as a good platform for multi-functional applications such as anti-counterfeiting and information encryption, owing to their good visibility, diverse colors and simple design. In this study, we design the Cs2NaTbCl6: Ce/Yb double perovskite single crystals, achieving visible green luminescence under various excitation sources such as ultraviolet, near-infrared (980 nm) and X-ray. The possible emission and energy transfer mechanisms between Tb3+ ions and Ce3+, Ce4+, Yb3+ ions under different excitations are discussed in detail. Our work skillfully takes advantage of the Tb3+ ions acquiring the transferred energy from non-luminescent Ce4+ ions and luminescent Ce3+ ions, broadening the ultraviolet response and improving its stability. The luminescence intensity of Cs2NaTbCl6 double perovskite single crystal was increased about 40 times under 343 nm excitation by doping Ce4+ and Ce3+ ions, which shows that Ce4+ and Ce3+ ions doping effectively introduces a new excitation band. Furthermore, diversified anti-counterfeiting modes are fabricated to highlight the promising applications of Cs2NaTbCl6 double perovskite systems with tunable luminescence in advanced anti-counterfeiting, paving the way for future research on the multi-light sources luminescent materials.