Color-tunable luminescence and energy transfer of Eu³⁺/Tb³⁺ co-doped borophosphate glass for anti-counterfeiting

Eu3+/Tb3+ co-doped borophosphate glass was synthesized by a melt-quenching method for the luminescence color-tunable performance. Under the excitation of 373 nm, the Tb3+-doped glass exhibited a very strong green emission at 544 nm, corresponding to the electron transition D-5(4)-> F-7(5) of Tb3+. The emission intensity and lifetime of D-5(4) level of Tb3+ dropped with the increase of Eu3+ co-doping, whereas the emission intensity and lifetime of Eu3+ at 615 nm increased, confirming the existence of energy transfer from Tb3+ to Eu3+. Additionally, the color-tunable luminescence of the borophosphate glass was also realized from green region to orange-red region through shifting the Eu3+/Tb3+ ion concentration and the excitation light. There was little difference in emission intensity of Eu3+/Tb3+ co-doped borophosphate glass under working temperature between 303 and 483 K, manifesting excellent thermal stability. This study indicated that the Eu3+/Tb3+ co-doped borophosphate glass could become a promising candidate for the applications of anti-counterfeiting technology.