Broad-Band Excited and Tunable Luminescence of CaTbAl₃O₇:RE³⁺ (RE³⁺ = Ce³⁺ and/or Eu³⁺) Nanocrystalline Phosphors for Near-UV WLEDs

Abstract

Here, we demonstrate a novel donor-intermediate-receptor energy transfer model through a Ce³⁺ → Tb³⁺ → Eu³⁺ scheme in a CaTbAl₃O₇:Ce³⁺,Eu³⁺ nanocrystalline phosphor. A new type of CaTbAl₃O₇ and CaTbAl₃O₇:RE³⁺ (RE³⁺ = Ce³⁺ and/or Eu³⁺) nanocrystalline phosphors were prepared by a simple sol-gel method. There exist efficient energy transfers of Ce³⁺ → Tb³⁺, Tb³⁺ → Eu³⁺, and Ce³⁺ → Tb³⁺ → Eu³⁺ in CaTbAl₃O₇:RE ³⁺ (RE ³⁺ = Ce³⁺ and/or Eu³⁺) nanocrystalline phosphors. With near-UV or UV light excitation, the as-prepared CaTbAl₃O₇:RE ³⁺ (RE ³⁺ = Ce³⁺ and/or Eu³⁺) nanocrystalline phosphors' luminous color can be regulated from green to green-yellow, yellow, orange, and orange-red by adjusting the doping concentration, categories, and different proportions of codoping Ce³⁺ to Eu³⁺ ions in the CaTbAl₃O₇ matrix. The luminescence mechanism with respect to the CaTbAl₃O₇:RE³⁺ (RE³⁺ = Ce³⁺ and/or Eu³⁺) nanocrystalline phosphors has been tentatively proposed. Due to their excellent luminescence properties, the as-prepared CaTbAl₃O₇, CaTbAl₃O₇:Ce³⁺, CaTbAl₃O₇:Eu³⁺, and CaTbAl₃O₇:Ce³⁺,Eu³⁺ nanocrystalline phosphors exhibit bright prospects in NUV-LEDs and other photoelectric field.