Advanced Anticounterfeiting Technologies Leveraging High-Efficiency Visible to Near-Infrared Luminescent Lead-Free Double Perovskites

With the rapid development of markets and economies, various brands and markets have raised higher demands for optical anticounterfeiting technology. Lead-free halide double perovskites with broadband self-trapped exciton emission have excellent properties such as good visibility, diverse colors, and simple designs, making them outstanding materials for anticounterfeiting and information encryption applications. In this study, we successfully synthesized lead-free halide double perovskites with dual emission centers by doping Sb³⁺ and Cr³⁺ into Cs₂NaScCl₆. The blue emission (445 nm) originates from the self-trapped exciton emission of the [SbCl₆]^3- octahedra, while the near-infrared emission (980 nm) comes from the luminescence of the Cr³⁺ ions. The near-infrared emission (980 nm) achieved a quantum efficiency of up to 71% through efficient energy transfer among multiple emission centers. Finally, various anticounterfeiting patterns were realized through screen printing samples. The research results provide inspiration for designing lead-free halide perovskites with efficient tunable luminescent properties.