Brilliant emission from Cs3YF6: Tb3+/Eu3+ under deep ultraviolet light excitation for water-sensitive anti-counterfeiting applications

The cesium-based fluoride Cs 3 YF 6 has increasingly attracted curiosity due to its potential in up-conversion luminescence applications, signifying a possible revolutionary change in the next generation of lanthanide-doped luminescent functional materials. However, the nature of the photoluminescence process involving Cs 3 YF 6 has still not been studied in detail. Developing Cs 3 YF 6 luminescence applications is an intricate endeavor. Herein, we present the optimal doping concentration required for Eu 3+ and Tb 3+ doping in Cs 3 YF 6 . Meanwhile, by spectra analyses and theoretical model simulations, we have been able to decipher the intricacies of the energy transfer interaction that transpires between Tb 3+ and Eu 3+ ions. Furthermore, a water-sensitive fluorescence response system tailored for anti-counterfeiting applications was designed, which relied on the superior luminescence characteristics of Cs 3 YF 6 doped with Tb 3+ /Eu 3+ under excitation at 254 nm, whilst simultaneously exploiting the easily deliquescent nature of Cs 3 YF 6 . This work not only enhances the understanding of Cs 3 YF 6 materials in the field of rare-earth luminescence but also introduces a novel anti-counterfeiting strategy, that propels the development of applications for rare-earth-doped fluoride materials.