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The efficient energy transfer in La 3 GaGe 5 O 16 :Cr 3+ , Yb 3+ /Nd 3+ and La 3 GaGe 5 O 16 :Cr 3+ , Yb 3+ , Nd 3+ was investigated in detail. In this phosphor, Cr 3+ acts as the energy absorber (250-700 nm) to sensitize Yb 3+ /Nd 3+ in La 3 GaGe 5 O 16 . Under excitation at 418 nm, La 3 GaGe 5 O 16 :Cr 3+ , Yb 3+ phosphors exhibited a broad emission band in the near-infrared (NIR) region located at 976 nm (La 3 GaGe 5 O 16 :Cr 3+ , Nd 3+ at 1056 nm), which was attributed to the 2 F 5/2 - 2 F 7/2 transition of the Yb 3+ ions ( 2 F 3/2 → 4 I 11/2 transition of Nd 3+ ). Moreover, a Nd 3+ ion was introduced into La 3 GaGe 5 O 16 :Cr 3+ , Yb 3+ . The analysis of excitation spectra and decay time proves that Nd 3+ acts as a bridging ion in the system. This can be used as a new strategy to enhance the energy transfer in Cr 3+ , Yb 3+ co-doped phosphors, and these phosphors have potential applications in NIR spectroscopy regulation.

With the rapid development of technology, information security has always been considered a major challenge. In this work, the excellent combination of persistent luminescence, photoluminescence, up-conversion luminescence, and thermo-luminescence in a particular material Zn 4 B 6 O 13 :Tb 3+ ,Yb 3+ synthesized via a solid-state reaction is reported, which can be used for the information encryption and anti-counterfeiting. Tb 3+ ions were chosen as the emitting centers for multimodal emissions, and Yb 3+ codoping can be used as electron traps and sensitizer to adjust trap distribution and efficient up-conversion luminescence in rare-earth-doped luminescent materials. Besides, the as-prepared luminescent materials exhibit high thermal stability and excellent water resistance. On the basis of these properties, the samples were used to print luminescent images through a screen printing process on the film and banknote. The luminescent image in a film is showing different patterns and on a banknote is showing green emissions under different stimulations. These multimodal emissions demonstrate that the as-prepared sample is suitable for advanced information encryption and anti-counterfeiting.