Long-lived Photon Upconversion Phosphorescence in RbCaF₃:Mn²⁺,Yb³⁺ and the Dynamic Color Separation Effect

The development of luminescence materials with long-lived upconversion (UC) phosphorescence and long luminescence rise edge (LRE) is a great challenge to advance the technology of photonics and materials sciences. The lanthanide ions-doped UC materials normally possess limited UC lifetime and short LRE, restricting direct afterglow viewing in visual images by the naked eye. Here, we show that the RbCaF₃:Mn²⁺,Yb³⁺ UC luminescence material generates a long UC lifetime of ∼62 ms peaking at 565 nm and an ultralong LRE of ∼5.2 ms. Density functional theory calculations provide a theoretical understanding of the Mn²⁺-Yb³⁺ aggregation in the high-symmetry RbCaF₃ host lattice that enables the formation of the long-lived UC emission center, superexchange coupled Yb³⁺-Mn²⁺ pair. Through screen printing ink containing RbCaF₃:Mn²⁺,Yb³⁺, the visualized multiple anti-counterfeiting application and information encryption prototype with high-throughput rate of authentication and decryption are demonstrated by the dynamic color separation effect.